Likely that would just mean that the troll company would pay the same upfront sum to the owner for the right to "represent" them and sue other companies and keep any revenues.

Also, consider when StartupX is bought by BigCo., and BigCo wants to simply keep the company running exactly as it was. Clearly someone else is controlling the patents than the original owner of the company.

Patent trolling is probably unavoidable, but I'd say much less likely when it's initiated by individuals. Legitimate claims must be accessible, and the courts need to be the test.

Your second point cuts to the heart of the issue, should patents be treated as traditional assets? One possibility: Once you sell your patent, it loses legal protection and becomes merely a trade secret.