I'm in my 30s. When I was 15, texting in the razr era was just as ubiquitous in my school as it is for anyone right now. Sexting, gossip, flirting, hanging out, all of it, all day, everyone. My sisters could even touch-type entire essays to their friends under the dinner table while they ate and were not allowed on their phone.

There wasn't any image content, but you certainly don't need images to have messages you want to keep private.

I wouldn't want anyone I know going through any of my private conversations line by line. I don't see how razr 2004 vs iphone 2019 is any different in that regard.