I think there's a case to be made that understanding of architecture has improved over the centuries - as one would expect; it's hard to keep architectural techniques a secret when part of their function is to have obviously visible products. But the increase hasn't really been qualitative, though. People have been building stone castles in Westeros for a long, long time - there doesn't seem to have been a rate of progress parallel to our own, where people went from wooden hillforts to stone castles with elaborate defences in a few (five or six, at least) centuries. Instead, the determining factor in whether or not one rules from a multi-tiered, sprawling fortress-city like Highgarden apparently is, or from a glorified brick shed, seems to be the availability of resources for construction, and the mechanics already in the game model that well. There's no shortage of brilliant architects, we have to assume, based on the architectural marvels scattered around Westeros (and Essos - the Titan of Braavos, for instance). There is a shortage of gold to pay them with, though.
We know that metallurgy is static, because Valyrian steel is still unrivalled by castle-forged steel, and castle-forged steel varies considerably in quality depending on the smith (much as everything else, as described above). There evidently aren't generalisable, consistent methods that would result in an accumulation of best practice over time, which isn't surprising, given that we have little indication of the widespread existence of guilds which could preserve knowledge of best practice. That said, it also seems to be at a level significantly higher than Mediaeval Europe, in some respects - metal can be coloured without compromising its quality, for instance.
Part of the technology mechanics in CK2 model diffusion. That doesn't seem to happen, either. Look at the relative sophistication of infrastructure in Essos compared to Westeros, despite the more or less continuous contact between the two continents. The impression I get is that Winter causes social stagnation, like a giant climatic reset button, such that there's no motor for technological progress on the paradigmatic level, and the Citadel is responsible simultaneously for preserving existing knowledge through Winter and limiting the potential of any new discoveries that might disturb things.
There probably has been technological progress over the last 8000 years. It's not surprising that people don't realise it in the books; in Mediaeval Europe, people tended to depict periods of history thousands of years in the past as if nothing had changed. Equally, though, I doubt there's been much technological progress since Aegon's landing; as I said, it looks like there may have been decline since then, as the Valyrian technologies he introduced haven't been generalised. Given that people are very unlikely to play the same game for thousands of years, technology points would need to nerfed so hard they might as well not be there.
On the other hand, you could argue that Westeros's recent history has seen social and political upheaval of a scale and duration far greater than anything since the conquest, and that might act as a motor for technological progress, at least when it all dies down. We've seen hints of that in the books - the refurbishment of Harrenhal, Cersei's ships, the use of wildfire, and so on - but nothing really substantial yet, and two of those cases are unlikely to be generalised for reasons discussed above. Cersei's ships could be, I think; and it could be simulated, since you can't change how many people fit in a ship with technology in CK2's engine, but you can increase ship levies.