A very good question to which I have no answer. There is no stable solution. Institutions will always tend toward capture, convivial tools will always face cultural erosion, and the best we can do is build things that make the cycle slower and less catastrophic.
Discussion
I look at it little similar to "evil". How we can restrain people from being evil? We can't... it's structurally impossible. Only way is culture, moral education, shared values passed down through generations. But these also fail over time. I really don't think there is an answer to that, and I don't know if we need one.
Another way to put it is that there's no static solution to problems in a dynamic system. Which means we have to accept our role as temporary agents within that dynamic system, pushing in the direction that seems best to us, knowing our efforts or vision aren't determinative. Still, there have been other epochs in history in which mechanism wasn't in the driver's seat, and I'm sure there will be ones in the future that are qualitatively different. Letters from Lake Cuomo by Romano Guardini gives me some hope for this.