Conventional paper-type legal agreements exist already for this kind of thing, and will mature further as jurisprudence and experience are developed. They don't introduce much centralization that I can think of. They are mostly P2P agreements about the guarantees given to token holders.

On top of that, smart contract mediated investments can have much more additional guarantees. Projects like Aragon are creating DAO governance UIs that are on-chain, usable (from a UX perspective) and transparent for token holders. They allow holders to vote on transfers of funds, or monthly capital allocation, with the possibility to withdraw funds if they deem the operation of companies irresponsible. This a programmable financial infrastructure: the tools are there to build whatever you can come up with in terms of governance.

Besides DAO governance platforms, what will compel executives, for the cases where this applies, is the same thing that compels them right now: financial incentives, and the threat of prosecution. Are the guarantees comparable to those you get from a CEO on a NYSE traded company? Not by a long shot, this is the wild west right now.

But in keeping with the "Internet of Money" metaphor from my other comment, lack of controls and accountability didn't prevent Wikipedia from displacing the Encyclopedia Britannica.