If you took a man from England in 1066AD and dropped him in England in 1766 AD he’d cope. It was still an agricultural economy, still based on class, the wider world still fought regular wars with small states run by hereditary aristocrats, still had slavery. The biggest change would’ve been the Reformation.
Medicine was still leeches and opium and no-one new what a “germ” was. One of the last big outbreaks of Cholera in London was in 1854, everyone thought it was caused by “miasma”, bad air, until one pioneering doctor got the local pump water shut down.
That doctor was, of course John Snow.
After the Cholera was gone, they re-opened the pump. It was another ten years before the wider medical community really began to accept that miasma was a myth.
Progress isn’t linear and it isn’t always progress.
The Romans had better sanitation than any British period of history until the Victorians and the Romans didn’t know what a germ was either.
The big invention that Westeros lacks in the movable type printing press.
Billions of ideas have been written down once and lost. Moveable type made it faster and cheaper to reproduce information and multiple copies let more of it spread and survive.