Having the opposite experience with it as a small team, and I can see how it would work great in my past large teams. I bet you're gonna have the same complaints about any API you use not just tRPC (junior developers not thinking about interfaces).
Make devs slower so they code smarter?
More friction is just that, it just frustrates devs it doesn't make them code better.
tRPC enables good teams to ship faster. Less friction means doing what the team was already going to do anyway, but faster.