That's not the question.
if we avoid running ancestor simulations for the purpose of maximizing the probability that we are not in a simulation, is it valid to, based on this fact, increase our credence in not being in a simulation?
That's the question, and the answer is "yes."
Unless you round sufficiently small increases down to zero, which is what people generally do. If somebody asked me that, and I estimated that the difference in probability was .00000000001, then I would answer "no".
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Of course, for "every Monday", the last one should have been dated July 22-28. *cough*