I'd say that the bigger argument against "nothing is worse off if it is encrypted" is that this takes precious time.
Technically this was fairly complicated to do, but cryptographically nothing much really changes, except that now more things are encrypted.
Now, if your TLS implementation just presents as a shim layer between a TCP port and your socket code then this may mean a significant rewrite, but again that's not about cryptography it's just an engineering problem.
Performance and power consumption of low-end devices.
If they use the encrypted Googleprotocol using the Googlebrowser to connect to the Googleweb, you can't do that.
I get that it's important for Google to encrypt what happens between their browser and their servers, but the rest of the world has different requirements.
eta: Or at least the ones where one end is a $30 phone someone bought off of Amazon that has no vendor support and the device has no CLI or debug tools available.
The function in question can completely and correctly be implemented only with the knowledge and help of the application standing at the endpoints of the communication system. Therefore, providing that questioned function as a feature of the communication system itself is not possible.
Applications vary in what needs encryption and how that encryption is implemented, so it is better to leave this to them to implement; otherwise, all applications may suffer the cost of your protocol's encryption implementation without getting the actual encryption that they need.
[1] http://pages.cs.wisc.edu/~bart/739/papers/end-to-end.pdf
2) QUIC explicitely doesn't use TLS but something different, so indeed, not everything needs TLS