Many people in the cryptosphere fail to recognize the fact that lots of centralized entities competing against each other can be a powerful decentralized force for the good of society. The key is, as you say, for folks being able to opt-in and opt-out of those systems they like or don't like, and to be able to do that with minimal switching costs. It's the decentralized nature of individual consumers each choosing which systems to use and which ones to shun that fosters innovation and advancement (or, testnet prototyping, to use your terms).

The great thing about crypto is that it is an opt-in governance system. If you don't like how the government works, then take your value and leave. The attention economy is here, and the whole centralized vs decentralized argument is so misrepresented It's difficult to know which end is up.