The American Dream kind of died. It died in two ways, and it's important to keep them separate.
First, the American Dream died (or at least got very sick) in that the path from high school graduate to high-paying job got very narrow. This was because other countries rebuilt after WWII, and outsourcing happened, and the US culture changed from more "we're all in this together" to more "I got mine, you can starve".
Second, the American Dream died even for those who got the well-paid jobs. They found out that it wasn't enough - that they needed something more than more money. Material prosperity is not enough, and more material prosperity won't fix it. Humans need something more, and we aren't getting it.
We're not getting it from technology, either. We don't need better graphics and instant movies. We don't even need social media - or at least, we don't need what social media has turned into, making us a slave to dopamine hits.
With that going on, how do people view tech? As a way to get rich? Well, that's probably not going to work out, at least not for most of us, and even if it does, all it gets me is money. As a means of making the world better? Yeah, how's that working out?
We're feeling the lack of something, and money isn't going to fix it, and tech isn't either.
I think that's what changed. People thought that tech could make the world better, and make them rich along the way, and now they see that tech can't fix what we need fixed, and being rich isn't enough.