Why would someone who has stood up to the Russian government multiple times, had a company taken away from him already for not being compliant and is now living in exile hand control of Telegram to that same government?
Secure messaging is hard, most people when producing secure messaging will produce poor secure messaging - it doesn't mean they've been compromised by a government.
It's one thing to get some security wrong because its "hard." It's another to not fix those problems when people explain how and why you did something wrong.
RSA encryption is theoretically breakable by quantum computers, but people still use it and gonna be using it until someone break it.