This is not true for all. Many here do buy parts, and pay for events. There are some that don't, and other that just want/have to make the best use of the funds they have available (re my post about not using the Aero hubs).
I don't think that as a category, AMCers are really much stingier than a comparable bunch of car nuts.
When there are 100,000 Chevy fans, 1% of them are spending big bucks on crate motors and rotisserie restos; but 1% of 1000 AMC fans is just not a big number. There's more like a million or two Chevy nuts; Jeg's has a separate catalog for them.
A good number of the AMXs I see at even local events, most of thme don't look like stingy half-assed jobs, they mostly look f'ing great. Rarely do you see a botch job, but a fair proportion are "low bucks". That's usually checking account balance not tightwad status.
At local events I see DOZENS of total crap Chevy and Ford stuff, real botch jobs. There's certainly many of them in the same sort of camp as our (just an example) AMXers, and a few big bucks jobs, but there's that proportion again.
While I think it's partly true AMCers don't take AMCs as seriously as maybe they ought to (the sort of thing John Mahoney rants on) but most AMCs (not most Ramblers...) are just now getting to an interesting age, where actual perspective can take place amongst the non-brand-fanatics. Lots of other makes have already gotten old enough such that their "classic" designs look it. Even 10 years ago a lot of AMCs were just old cars, in spite of a few prescient amongst us.