I don't know about that. The two main cases I remember (uki rower and Sam Riley) were complete contrasts for resources. Rowers earn jack.
On Cass, I think he was pretty well backed too. Going off a long memory, but pretty sure he had club and WAFL agreeing his use was incidental, and I think he was given some decent legal representation for his first appeal, and the latter ASADA one (no idea who paid, but assuming its not him given what a WAFL player earns).
I'm not necessarily saying the resources of the individual athlete but the organisations backings them. When you're talking Olympic sports they have the backing of the state, that whole national pride thing. Carl Lewis failed three tests, got off each time on inadvertent use, but he wasn't the only one at the same time 116 American Olympic athletes failed tests and got off for inadvertent use or therapeutic use, individually they are nobodies, but as part of the American Olympic team the whole national pride thing kicks in.