You say this could make you more competitive and that might be the case - but ultimately I get the impression you're less likely to be acquired (fair enough, maybe you definitely don't want that) and/or/thus more likely to shut down.

Realistically your pledge means nothing if you go bankrupt and shut down. Your startup could still fail and nobody really has any recourse in general. You could probably find ways around that but forcing liability on founders will probably make this less likely to catch on.

An acquirer is going to be held to these presumably, and they probably can't just go bankrupt to avoid them - so that's less likely to happen. Maybe that's what you want but it cuts a big exit path out for founders - and acquisitions aren't always terrible for users. I wouldn't be surprised if there exist acquirers for some startup that would keep users happy for >X years but not commit legally to doing so for X years.

I guess there's a bit of a cycle and it really leads to the pledge being worthless. Less likely to be acquired + can't pivot for X years -> keep doing the same product -> but it's losing money -> no viable exit, no pivot -> shut down.