Yes, another case of blame everything on the boomers. We all actively voted for sky high house prices, so we could boast about how much our houses are worth, we spend all our money on cruises, while telling younger people that if they didn't have iPhones they'd be able to afford a house....
Anyway, I can imagine that the odd little sweet or piece of chocolate is a last resort of grandparents valiantly doing their best to help with childcare that would otherwise cost a fortune, and knackering themselves in the process.
The other day - dd was staying over with Gdcs aged 1 and 2 - I admit that we did use TWO chocolate buttons in order get the elder in the bath - she was kicking off about it - and her teeth brushed.
I hadn't even bought the chocolate buttons for Gdcs, they were left over from Halloween. Dd was only too glad that I had them available - we were both pretty exhausted by then. In general they have very little in the way of anything remotely junky.
I'm sure there is the odd grandparent who allows endless junk and sugar, but I bet there are just as many parents who do the same.