But this has never been true. Lots of valuable, productive, and loyal Nazis ended up in political prisoner camps.

Because that kind of kleptocracy runs on constantly fighting factions and incentives and selfishness. The core belief is selling someone else down the river because you can.

there's a difference between being a good and loyal fascist and being in with the fascists. you've actually hit on it. those valuable, productive and loyal nazis were allowed to do whatever they wanted without regard to the law when that benefited the party, then that same behavior that was legal and encouraged was what got them kidnapped and murdered by the party as soon as the winds shifted. The core belief of fascism is two-fold: selling someone down the river because you can and believing that either through compliance or raw power you'll never be the one sold down the river.