^not the person you asked, but I do think about this topic from time to time.
I was conscious through all of the 90s (starting 30 years ago, like you were saying) and I definitely felt that, compared to today, the dollar went further. The number on a paycheck might have been smaller, but it bought more stuff. I think that's a lot of the anger, it takes more and more to not even live "the good life" but just to get to "just OK" these days. Everything from gas to food and day-to-day stuff now costs more. It feels like doors are shutting. Nowadays you need more education that's more expensive that you need to be smarter to even be able to learn it in the first place. Even if you can somehow afford it, anything that pays even enough for "just OK" is getting more technical and difficult to understand and there are only so many positions available. The world is getting more complicated, but people aren't getting more intelligent to keep up with the pace of technology (I'm not anti-tech at all by the way, I think scientific and technological progress is good but I'm not sure what to do about this situation where you need to know ever more complex things just to be "OK"). I think competition is getting a lot worse, and it's bringing out the ugliness in people in all forms of life. It used to feel like there was enough to go around, and enough opportunity to move up in the world should you choose to do it. Now it's feeling less and less the case. Today it seems like if you're not winning, you're losing. There's no middle ground anymore.
It's frustrating when people tell you to "just be content", when what you're supposed to be content with is crappy, and getting increasingly crappier. What you're supposed to be content with, isn't at all motivating or inspiring or invigorating. It doesn't make you want to get up in the morning and face the day. You feel stuck, unable to make any progress. You don't feel like you can really get anywhere that's any good, so it's not meaningful. It's getting harder to see any reason be hopeful for the future.
Also, and this competition might feed into it, but identity politics have gotten worse. It used to feel like your political alignment was something that just came up now and then, around voting time, and it wasn't that big of a deal. Now it's in your face every day, and it's like the two sides want to kill each other. At the same time it's feeling like the people on top, regardless of party, don't care and can't even be bothered to pretend they care anymore. They just want more money for themselves and their friends and associates.
Well. That's my take. Not saying this is the answer. Just how it seems to me.