How long till the watchtower admits their mistakes and do everything possible to rectify them?"
Those are actually two separate good questions:
"How long till the Watchtower admits their mistakes?" - If past history is any indication of pattern: Never. They may change policies under the radar and ret-con their history. But admitting that they made a mistake? Never. Never. Never.
"How long till Watchtower...do everything possible to rectify them?": I imagine like any company the GB consults with a professional Actuary that provides the financial risks of maintaining any one position/doctrine (e.g. pedophilia, blood, etc.). This is no different than when a company evaluates a safety feature and computes the cost of implementing it vs. the possible wrongful-death lawsuits. They go with whatever number is lower. The GB almost certainly has done a similar calculation with their insurance actuaries and attorneys. I can imagine they weighed the perception/image cost of changing their doctrine (and admitting mistakes) vs. the possibility of lawsuits. Very sang-froid...So until the lawsuit costs are higher than the change in policy, it is likely that nothing will change. And, changing now would be to admit a major mistake which is a pretty high cost for them. We shall see...