In my experience it is less about huge amounts of money, and more about being bothered to get it right. In the case of the Bristow sims, individuals with deep technical knowledge of each type (Subject Matter Experts, to use the in-vogue term) each put a lot of time and effort into perfecting the details of the systems etc post-delivery, such that we now have pretty good and representative sims. The cost of that was perhaps a man-year's salary or two, a drop in the ocean in the great scheme of things, even as outrageously over-paid North Sea pilots!
But without that input - ie just paying money to a Sim builder and expecting to get perfection back - they would have had as many and probably more issues as Geoffer's sim seems to have. The responsbile and knowlegable individual driving the finishing touches seems to be what was missing when his sims were built. Not that expensive, but you need to have the right person.