The article below argues that the real use case for breaking encryption is to catch everyday criminals, not to go after shadowy Bond villains. Would the public still go for it, if they looked at it this way? Probably not...
The Encryption Debate Isn't About Stopping Terrorists, It's About Solving Crime https://www.lawfareblog.com/encryption-debate-isnt-about-sto...
Edit: And most everyday criminals are not technologically savvy. Half of them probably have a hard time using Telegram safely.
In practice even the tech types weary of using and maintaining truly secure solutions. So if they outlaw backdoor-less solutions then companies won't support them. And without commercial support the options will dwindle.
And even donation supported projects like Truecrypt will fold under pressure.
Crypto isn't a one-person job
It's not feasible to ban people from using their own encryption unless you plan on severely restricting their freedom.