Even though Bitcoin, the platform itself relies on trustless transactions, the actual software relies on the trust we put on the development team.
If you didn't trust them you wouldn't download their software would you?
This is the "just don't update" argument and it's not going to fly forever.
But who would vote?
Merchants, exchanges, pools, payment providers ... anything is better than the centralized and totalitarian system currently in place.
Stop your nonsense. You're essentially calling a democratic system which is open to corruption. That would never work in this ecosystem. Most of the people/services who vote, would be paid to vote for X or Y.
The don't upgrade argument is great. As long as services don't upgrade (which they won't if it is something bad) we are fine. If it had worked so far, why would it not continue to do so?