There are also work arounds for the a6300, but how do you know a similar FW update will never be released for it?
...yes, and the a6300 costs $2,000 less. I mentioned the lack of IBIS, which isn't a big deal if you use stabilized lenses or a gimbal, or both. I haven't seen a side-by-side comparison of DR between the a6300 and A7Rii, but I'm willing to bet the difference is negligible. Rolling shutter may be slightly worse on the a6300, but is it enough to warrant spending $2,000 more for either of the other two cameras? Depends on what you shoot and how much you have to spend.