Companies absolutely can pay people solely to combat ad blockers. That will always win. Facebook doesn't have a "system" other than always changing their system. Any company can constantly change how they display ads. The ad blockers are just always playing catch up until the corporation exhausts the volunteers energy.
If the solution is to get new volunteers to keep up the work, why don't we have people willing to take on that role? Most people that have the know how arent using facebook anyway, so there's no motivation from them.
Without legislature to enforce some rules on corporations, the ones with the money will always win.