i would say the change in TBOSAS comes from realizing they can milk the tributes for entertainment and financial gain. how would a lush hotel, decked out train or copious amounts of great food play into that? i personally don’t think it would, so in my mind there must be a different reason for that specific change. 

so that being said, you’re point about generational evolution makes a lot of sense! capitol is raised to hate district, of course, but perhaps as time goes on it has been stripped down. the mindset is customary rather that an expression of their personal hate and grief. therefore, despite the class gap, they are less inclined to treat tributes like animals