I think the democracy activated kill switch may be difficult to coordinate and could lead to stagnation. Unless there is a vested interest in monitoring and participating in voting to kill or not, then the participation in voting could be low, making it vulnerable to organized groups (possibly malicious, competitors etc).
On the other hand, a market activated kill switch is harder to manipulate (since you have to manipulate the price) and is more likely to be decisive since it directly values the progress of the project. There is no need to round up everyone and agree on killing the project, you just vote with your money. Although this method is more prone to industry wide price action, and could end up being triggered in periods of high volatility, so some buffer against that may be called for.