You can tunnel over TCP/UDP. You lose a number of privacy benefits though

I2P as well

I know but using reticulum over TCP it's a sort of Tor(we already have it) Convert all application developed until now to reticulum it's impossible. And I'm not sure it can scale up with a billion of users, I think the routing could be a nightmare. Probably it can be used with a specific scope, like an emergency network.