The way to make L2s that scale far beyond what the base layer can accomplish is to align incentives so that users can exit without the provider’s permission.

You don’t need everyone to exit all L2s at once and the capacity to pay for that cost en masse, to properly align incentives for individual hosts/providers to be trustworthy. You simply have to make being honest more profitable than being dishonest.

The most important factor is unilateral exit, because without it the ability for the user to enforce anything at all regardless of cost just doesn’t even exist.