Curbs have onramps. Pretty much every corner and every driveway provides a ramp where wheeled vehicles can easily get on to the sidewalk. You will never have any difficulty pushing a shopping cart onto a sidewalk.
https://sdotblog.seattle.gov/wp-content/uploads/sites/10/202...
While things are improving in europe, many sidewalks still have a tiny step. Not high enough to be a problem for someone in a wheelchair but definitely for a loaded cart with shitty plastic wheels. Also it is not uncommon to have people parking where they shouldn't so you can't rely on it. In many part of the world people living in a wheelchair tend to spend a significant amount of time in the street instead of the sidewalk because of "stuff" that block their way on a regular basis.
It was signed into law in on July 26, 1990 by President George H.W. Bush. I hope you get to see a progressive man like George H.W. Bush in the White House again.
https://en.wikipedia.org/wiki/Americans_with_Disabilities_Ac...
The ADA is not a good thing. It's best known recently for forcing UC Berkeley to take down the lectures they used to provide over the internet for free. But it's been having very negative effects since it was enacted.
Page 4, for your reference: https://archive.ada.gov/briefs/uc_berkley_lof.pdf
Locally all supermarkets actually have locks at the entrace so that people can lock their shopping trolleys next to the cashiers.