They are always there, the next generation.They exist, but it's not the same. Not in the same numbers. You're right that a bunch of it is economy-driven, but every generation goes through hard times. Millennials (I assume you reference Millennials) like to moan a lot, but they had it easier than a lot of people before them. Millennials have never known food rationing, mass migrations because of natural disasters, gas shortages, a real war, or many other things that older Americans have.
They will have lived through a Great Recession and a pandemic
They weren't the first. They won't be the last.
they know that climate change is real
I'll give you that one.
it's only older people that are holding them back.
That's simple ageism. The "older" people created all the things you take for granted: computers, space travel, cell phones, satellites, jet travel. You're standing on the shoulders of giants.