Honestly, in my experience the original stuff largely disappeared. I vaguely remember watching some of it back in the early 90's, but never in school. The holiday specials would be on TV if you went looking for them, but that's about it.

Snoopy was more ensuring than Charlie Brown, but even that was more "cute cartoon" than anything to do with any message.

Edit: I see some sibling comments that it's making a comeback, though I've no idea if any of it is all that faithful to the original.

Charlie Brown had a lot of Christian messaging reflecting Schultz's devout beliefs, and I doubt any of that will show up in whatever Apple and Target and current schools are putting together.

talking about snoopy, it was quite popular in france in the 80s, i even have a kid thermos (https://www.etsy.com/uk/listing/1478487195/thermos-snoopy-an...). but yeah it felt acultural to me at least (to be honest i would have said it was english)