Electric ovens in the US have required dedicated 40 or 50 amp circuits for decades per the NEC. Dishwashers, as well, have required dedicated circuits for a while but the 20 amp requirement is a more recent development (although it's probably been at least a couple decades).

Kitchens in general have required 20 amp general purpose circuits since at least the early 80s. However the NEC (but not the Canadian equivalent) allows for 15 amp duplex receptacles on 20 amp circuits so home builders looking to save a few pennies often use those. Besides, there are few if any, residential appliances out there that have NEMA 5-20 plugs. Then again hardwiring dishwashers was pretty common up until recently.