I don't think it's anything new really though.
I grew up in the 70s and 80s and we did have snacks - tuck shop at school at playtime, sweets from the shop in the way home, access to apples and bananas at home when we got in, etc.
Schools have had milk and fruit snacks for a long time - I think it was introduced when dd was very small, so at least 20 years now. Free for infants, encouraged to take on for older. Milk at playtime was around much longer,
Lunch at school is at 12pm generally. So it can be a long time before dinner at home. A snack when getting home, or after school during the walk home or drive to an activity isn't particularly unusual, or even bad.
The water at school thing has been around for a good 20 years, more or less, certainly when dd was little. Whilst it can be a pain in the classroom at times, I also remember not having access to water at school, bar lunchtime, and being very thirsty.