It's not the kind of problem, that can be solved with technology. There will always be people with access not loyal to the company and pissed at management.
Backups could be maintained on a regular schedule, including full router backups. Others in charge of this could be given create and append access to the backup systems, but not delete.
Once you delineate split rights and controls, then you can mitigate the severity of these attacks. Yes, douchebag-router admin can still zero out the routers. But you can be in business in less than a day with those configs logged.
Point in case, as parent commentator said, it's not the kind of problem that you solve with technology.
But thanks for assuming I'm some inhumane business exec, or a VC.