in my humble opinion the major reason is because people don't want to adapt to doing something different.
Sorry, no. It's because the CoH2 system in unintuitive and antisocial.
The evidence is clear - empty chat rooms with tumbleweed drifting around them. Compare them to busy CoH lobbies (lobbies more important than chat).
It's insulting for Relic to say "we're not using them properly."
Oh, and Steam? Why do I need to Shift Tab to have individual chats outside of the in-game overlay? WTF?
It's clunky. It's not user-friendly. It's shit.