Taking a first stab here at some outside-the-box thinking. Here goes!
A big "story" of Hadrian's Wall is the idea that so much was still intact until relatively recently -- say, the 18th Century. That there were still forts looking like forts with impressive walls and visible house remains. And that the Enclosure Acts and the Military Road utterly devastated this.
Following this, many modern scholars look at old reports of Vindolanda and say that as recently as near 1700 parts of the military bath house were still standing, and a nearby temple was still upright as well.
I'm not convinced.
First, Camden made clear that even by 1599 large swathes of the Wall were completely obliterated by human activity. Though he wasn't able to inspect the central sector, he gives good account of other long stretches where there was clearly nothing left to be seen. Second, when Horsley made his journey in 1725 (a generation before the Military Road was built), he encountered only bits and pieces that could be said to be standing "in the fourth degree" -- that is, with original stones on stones visible above the brush & rubble.
The earliest eyewitness to Vindolanda appears to be Christopher Hunter. Writing in 1702, he describes what seems surely to be the military bath house. He describes a lower room, and an upper room. Of the upper, he says it was "strongly vaulted above." To modern eyes/ears, that sounds like an arched vault, like the arched roof the bath house would originally have had. But the rest of the description doesn't quite wash.
First of all, he said that the upper room had "niches, like... Chimnies on each side of every corner or square." The term "niche" seems to imply that the side facing the room was open to the air; not that it was a hollow chimney pipe. The only area where the chimneys would appear as niches would be in the hypocaust area under the floor -- where the chimneys would -have- to be open to collect the smoke & heat.
This seems supported by another of his comments, that the "pavement of this Room, and also its Roof, were tinged black with Smoak." There would be no way that an actual room used within the bath house would be smoke-tinged all over, unless it had been destroyed in a cataclysmic fire -- of which there was no evidence.
Some would counter that his last statement supports the idea of an arched, vaulted roof: "The Stones used in Vaulting the upper Room have been marked as our Joyners do the Deals for Chambers." But the terms "Joyners" and "Deals" show that he was describing woodworkers using straight planks of wood (middle English "Deals"). An odd comparison for an arched roof.
15 years later, John Warburton uses the term "vault" in a much more pedestrian way, describing the hypocaust rooms as vaults (storage chambers or "for receiving the offal of sacrifices"). Perhaps it is in this vein that Hunter was describing two hypocausted rooms, flat-floored, flat-roofed, vault-like, blackened by soot.
Another argument is made that there may have been a standing Temple of Diana on the western edge of the vicus into the 18th Century. However, there are no reports from any 18th C or earlier eyewitness of anything standing; there were only columns and capitals found and taken away by stone masons. Pieces of columns and capitals are still found today, broken or reused in later buildings, so the find isn't that surprising. The association with Diana is also only based on the observation that many stags' antlers were found somewhere nearby, and that they -may- have been part of a ceremony for Diana.
In looking at all other building on and near Hadrian's Wall, none of it looks like it was meant to stand the test of time. Construction techniques that may have suited the warm Mediterranean surely were not meant to survive centuries of northern winters. Moreover, the vast reuse of Roman stone by late- and post-Roman workers for defenses no doubt took their toll on anything that had remained standing. While there's no doubt that some parts of the Hadrian's Wall frontier were in a better state in the 17th/early-18th C than they are today (Carvoran one of the best examples), there's no good evidence that any parts of Vindolanda were recognizable and upstanding to any significant height by the time the antiquaries could have gotten there and saved them.
The bath house 'niches' go all the way up, through to the roof. They do not 'stop' under the floor. It is an integrated system. They are chimneys really, piping hot air into the walls themselves. It would not be unreasonable for the plaster on the walls to have degraded to such an extent that the chimneys would have been open to inspection above floor level. The basement is not vaulted, it is merely covered. As the chimneys in the main rooms would have been filled with soot, once the covers were removed or exposed, this would fall into the room and be washed about with water from above (which gains entry through the exposed chimney stacks to create a sooty stain which would rapidly spread across the interior plastered surfaces). Giving Hunter the image he described. In fact the failing of the Roman baths house design in northern European countries is that water can easily penetrate into the basement system from the roof. This is why they eventually abandon the idea of using tile in the basements as the constant water erosion rotted them out. They are replaced by stone for this reason. The large stones marked with the masons numbers are the vault stones. We rescued some from the pre-Hadrianic baths which had fallen into the basement. They are marked in sequence so that they can be correctly assembled, like lego. If they were in position as described, the roof was still on.
Despite the fact that many of the 'historians' did not venture into areas where the wall was relatively protected, it was an area devoid of intensive farming or industry, hence its protection. Industry and farming are the main reasons for the destruction post Union of the Crowns. What makes Vindolanda amazing is the level of preservation for all of the buildings, including the later ones. Added to this, the lack of disturbance can be attributed to the large quantities of material culture that is recovered from even relatively late levels. This is in direct contrast to most sites in the area which have been subjected to much greater post medieval pressures including the eventual military road building. There is little doubt that the military road, government grants for land improvement during the Napoleonic Wars become the final tools for destruction. Although until the late 1960's, several miles of the world heritage site was regularly being destroyed in modern quarrying for the manufacture of the UK's motorways.
It would have been helpful if Hunter et al had been artists or were prone to doodling. But as they were not we are so much the poorer.