Yeah, Forgotten Realms is not a low-magic setting, but it is not that high magic either. Magic is rare. It is special. Wizards are rare. Sorcerers even rarer.
In both your examples (Thay and Netheril), magic is only "mundane" for a privileged few. Let's look at Netheril. There were the floating cities with the mages and apprentices and also there were the land towns with the masses of the common people living in the shadow of those floating cities. Not like every peasant had some cantrip at the ready.
Though, it could be different with races who have innate magic, like the drow for instance. They have probably a more intimate relationship with magic, than humans.
