> SDKs are an enormous effort to create and maintain for every HTTP API,

Hence the attraction of generating client and server stubs with gRPC

> Browsers (and by extension, websites) are not good examples of REST in practice?

The "client" of a website is a human being - and we are very good at interpreting dynamic content.

As an example: There are probably 100+ websites out there where you can book a ticket for a flight. It might be painful, but as a human, I can figure out how to navigate and book a flight on any of those systems.

I challenge you to write a REST client that can do the same.