MIxed bag here reliant on a power chair but overall I have to agree with you and i'm in NY albeit upstate not the City - thank God.
In my small neighborhood IGA built in the 60s and the same size it always was so picture your typical 1960s supermarket which by today's standards is small, I can ask for help and get it with a pleasant they're glad to. It's my go to between if I run out or get to craving something. Note: this is in a two-mile square village. Yes, I think that makes a difference.
Go to the larger town's my village resides in, not even the neighboring city's (not stating which one but note no capital on city - here in NY there's city and the City which means NYC) - quite the opposite experience akin to your wife's. There's no way in hell I'd live downstate. Not even LI let alone NYC. Sorry to those who it's going to offend but NYC/LI is hell on earth.
My daughter now tackles that for me and if she didn't, I'd use delivery instead though even that has changed. I was getting delivery for a while. The big supermarket handled it themselves and service was not only polite, courteous and friendly making chit chat small talk to an old lady while they unloaded my groceries but they would put my 12 packs of Snapple on the counter next to my fridge for me and my water on the opposite end (since I don't refrigerate that) without complaint. Just part of the job, ma'am, when I apologized because I have a bad habit of apologizing when I ask for a favor.
Now they've all gone over to Instacart which is a mixed bag just like all those kind of apps (uber, grub hub, etc.) and luck of the draw who you get as the driver. Naw, I have trouble getting to the IGA in winter at the other end of main street than me due to NY's six months of snow but if, for any reason, my daughter can't get for me, IGA's will suffice for all my grocery needs.
When it comes to Uber, I let them know mobility device (resort to walker with difficulty because powerchair ain't going in anywhere) and have been flat out refused for needing them to fold into trunk. And, no, it's not because too big for their trunk because to drive Uber or Lyft, your car has to meet certain specifications including trunk size and minimum trunk size is more than necessary for my walker. They just don't want to do the work of folding it into the trunk.
Not only what your wife experienced - I've had people start to go into an aisle see my powerchair and quickly leave before I could ask for help - but traveling in parking lots, on sidewalks anywhere in public, they seem to unrealistically expect a power chair to jump out of their way instead of walking their able body around it and I always drive on the right.
But when the sidewalk's too narrow and one of us has to go over the grass, the powerchair ain't going to do it, a-hole, like you nimbly can and should be grateful for Guess you won't know what you've got 'til it's gone.
But that baffles me, before my working legs were gone, I did realize that I could go over grass etc where wheelchairs could not. It baffles me this get out of my way wheelchair atittude. I mean how can they not realize this?
Thank you for the opportunity to also rant.