Sure; as noted in the thread, boosting is already a thing, so it can be paid for with any kind of payment.

Even if mining power were massively distributed, it's always possible for it to coordinate, even purely anonymously, to cooperate in such a scheme. If everyone's interests align, it can happen (maybe unlikely, today, but ... possible. Not sure econ. value of watching is high enough). Centralization makes it fragile, also.

Afaict the OP 'ethereum is dead because this adverts for tx fees scheme exists' is just stupid.

The downside is if the block is orphaned, no other miner will include your TX. You have to trust the specific miner you paid.