It’s less about science not being possible, so much as the society of the time not being the kind which would support it. Look at the actual ancient Greek, Roman and Chinese civilizations. They had a lot of natural philosophers. Some even had plenty of advanced for the time technology; novelty steam-driven toys, for example …
On The First versus Second Age
The key thing here is that when it sucks for people in the First Age, it sucks much more than it does in the Second Age. Sure, maybe nobody dies of cholera. But in the Second Age, entire cities aren’t transformed into living crystal or squid-monster. As bad as the Perfect is, he is much nicer than …