I’ve worked with a lot of Test Pilots, some were not TPS graduates – however, the vast majority of these TPs would (IMHO) have had little trouble graduating from TPS. Not everyone is given the opportunity to attend a TPS, so there must be other routes to becoming a TP.
I don’t think anyone is suggesting that graduates of a mil TPS are ‘Godlike’ – just that the training they get is superb and gives them the skill sets they need to start in the test world. Certainly the chop rate of the TPSs demonstrates that the course eminently passable (albeit hard work requiring a baseline level of intelligence) – rightly, only those who cannot achieve the standard, despite extra help, are discarded.