Is it now expected that frail old people in supermarkets should get out of the way of a healthy mother?

No, it's incredibly rude. I move my chair aside for old people to pass me because I was taught to let someone who might have a difficult time moving pass me as easily as possible. It sounds like the mother had an undeserved sense of entitlement.

Nope. You've just encountered another situation where somebody was incredibly incondsiderate. I hope what you experienced is not that prevalent, but I see many acts of rudeness these days and it boggles my mind. It appears that people care only about themselves and don't give a rat's a** about anybody else and their needs. It's too bad. I can't count the number of times I've held a door open and somebody walks through and doesn't say a word. Or when I say "thanks" to a cashier and they say nothing back. Also, I can't stand the way drivers tailgate, cut people off, and neglect to signal and it appears to get worse every day. I just don't understand why there are so many selfish people out there. It's very sad, but all you can do is just be kind and considerate yourself and try not to let the rudeness wreck your day.

Yes that's rude, not just for the older person, but other shoppers in general.

Say in a very deliberate slightly louder than normal voice "excuuuuuse me, just need to get around you, doesn't seem to be much rooooom, so sorry about that" <dripping with sarcasm> wideload mom should get the hint.

Manners are hard to find in a society that has no one respect for anyone other than themselves. Manners are derived from moral training and family stability with is often rooted in religion.

If people cannot respect themselves let alone others --- we do not have civilization.

Stop worrying about an isolated occurrence in the events of mankind throughout the history of the world.

Not around s.e.Virginia. Maybe that insensitive cow will live until SHE has difficulty walking. That's my wish.

some people are oblivious

just say, 'excuse me'.