It's probably a combination if reasons why it seems like there's less bullying.
Bullying is less physical now with online bullying existing. Also, it's difficult for outsiders to understand if someone is bullied if they don't bring it up.
E.g. some girl in my class was bullied in 8th grade, but it wasn't obvious to me as I wasn't close to them. For an outsider not paying particular attention making fun of someone a few times might just be friendly banter.
[...] transfer rooms. Not much time to flush heads in that span?
At least in my school there were 20min breaks after 90min of classes, so more than enough time to give someone a shower if they wanted. Edit: Altough I want to believe they had to be more careful so they chose less obvious forms of bullying.
I guess you aren't living in the US either.
The iPhone is extremely popular over there, especially amongst teens the market share is over 80%. Also, because of cheap SMS and MMS people actually continued to use SMS while e.g. most of the EU quickly switched to internet messengers.
At the same internet messengers started to appear, Apple released iMessage which is a internet messenger with an SMS/MMS fallback for chatting with non-iMessage devices. This experience is worse for many reasons, notably the terrible 500KB media size limit makes videos unwatchable.
Additionally, MMS group chats are a thing in the US. This means a single non-iMessage device in a group makes the experience worse for everyone.
This lead to most people using their pre-installed messaging app, which is a worse experience on Android (SMS) than on Apple (actually modern messenger). It's not an issue in other countries because people are accustomed to instantly installing WhatsApp on their new device.
Edit: As a teen, I didn't even know MMS could do groups because ten years ago it would've been prohibitively expensive anyway.