> You just can't compare the two.

You just did.

I was responding to the claim that Telegram wasn't providing a protocol or ability for developers to author their own clients.

And point taken—I didn’t know about this, so Telegram was not an ideal example. But, as you point out, it still is not quite a decentralized as email, and, as a protocol, does not have email’s universal character. But thanks for the interesting information.