I do think that’s the root of it. That, and the religion-based beliefs of some that wealth is a sign of God’s favor.
My father once asked me, didn’t I find my politics becoming more conservative as I aged? No, because the more I live, the more I understand how fundamental luck is to anyone’s success. Hard work alone is no guarantee. I was born white, to middle-class parents, who emphasized education, at a time when public college was still cheap, my degree was in high demand, and too young to be drafted to Vietnam. Hard work? Sure, but I had the great fortune to be born on 3rd base.
I really get irritated at assumptions that people “deserve” their financial success or lack of it.
Churchill (I think it was Churchill, anyway) famously said, "A young man who is conservative has no heart, but an old man who is liberal has no brain" or something like that. I suppose he was saying young people have nothing to lose yet, so they understandably tend towards idealism, while older folks are more invested in their society and have a lot to lose, so they tend to be more about protecting the status quo.
Maybe this was true when conservatism and liberalism were just about finances, and older people could reasonably be assumed to have "made it" and to live somewhat stagnant lives, surrounded by people like themselves. This is no longer true, and political conservatism in the US is about actually going back to an earlier era where many people would have fewer rights, not just about protecting a certain status quo, and about ignoring science and letting the planet go to hell.
Nowadays, liberals can be said to be protecting the status quo when it comes to things like reproductive rights, laws barring discrimination based on race of sex etc. They could also be said to be protecting the status quo when they oppose dismantling environmental protection or existing social safety nets and when they express concern about how quickly the climate is changing. Nothing can be "status quo" anymore in a warming world.
As for how politics shift with age, I suppose it depends on the person and on the community they live in, but I personally have grown more liberal in some respects (and I was always fairly liberal), and I see this happening with other family members too, save one, who was always more conservative than the rest of us (and now he's really far off in Trumpsville). The issues one cares most about can change out of shifting self interest, but personally, my job has broadened my sense of what young people are going through today, since I teach at a community college for a living. Maybe this is why academics tend to be more liberal? I consider myself a strong liberal, because I do favor adopting stronger protections for human rights and promotions of economic equality, not just opposing the changes backwards the GOP wants to make.
I also have non academic friends who used to be Republicans but no longer are, but I can only think of one former Democrat in my wider circle who has turned conservative.
One female friend who used to be fiercely conservative is now fiercely liberal. I think it's because she has experienced gender discrimination firsthand in her life and profession, and she has also experienced what happens when a public-sector IT department outsources its workforce. Basically, she was laid off then hired back at a fraction of her former salary with no benefits. That would tend to shake anyone's faith in the powers of the free market.
Sometimes living one's life shifts one's views towards a more liberal stance, rather than the opposite. Or maybe the current political climate has simply tossed old-school conventional wisdom on its head.