In the US, the Pete Peterson Institute has been actively inciting inter-generational strife for at least 25 years, as a means of convincing younger voters to privatise Social Security -- Wall Street wants its hands on that money.
They argue that the Social Security Trust Fund is going bankrupt -- and this is true, it is. But it was MEANT to empty out. Prior to 1983, there was no Social Security Trust Fund. Social Security was funded on a pay-as-you-go basis, with working generations funding the retired generations. in 1983 Congress decided the Baby Boom generation was too large to be supported in retirement by younger generations and so they doubled payroll contributions as the last of the Baby Boom entered the workforce and set up the Trust Fund, designing it to empty out when the last of the Baby Boom generation died out, at which time Social Security would revert to pay-as-you-go funding.
The Baby Boom generation are the ONLY generation in the US, actuarially speaking, that is/has been funding both their own retirement and their parents' retirement.
The younger generations in the US have been sold a big lie that the Baby Boomers are "using up" all the retirement benefits and there will be none left for them.
Al Gore, when he ran for president, talked about putting the Social Security Trust fund in a "lock box" so that the monies allocated to it could not be used for other reasons. The press made enormous fun of him for that. But in fact, without being in a "lock box," the US government has "borrowed" from the Social Security account to pay for tax cuts for the wealthy. The press now say that the Social Security Trust Fund is stuffed with "worthless" IOUs, which is ridiculous and pure propaganda, because what they are filled with is US Treasury Notes backed by a government sovereign in its own currency (as, by the way, the UK is -- which makes it functionally impossible for either government to go bankrupt.)
I think much of the OK Boomer shit is coming from the US, and this is the reason why. It doesn't really make sense in a UK context, given that the UK didn't have the enormous birthrate bulge the US did in the aftermath of the war, in large part because the US did not endure the loss and privation the UK did in either the war or its aftermath.
It's also pretty silly as a sorting, in my opinion -- there's a big difference in the life experiences of people born in 1946 vs. 1964, not least of which, in an American context, is the draft and the Vietnam War.
Younger US generations truly believe the Baby Boom generation has devoured/will devour all government retirement benefits, leaving them nothing, and many in the older generation believe that too -- which reveals, more than anything, the extent to which Americans know next to nothing about banking, finance, and economics.
But it's that belief that's fueling a lot of enmity, along with the propaganda that the Baby Boomers are responsible for climate change or governmental failure to act on climate change -- which is a nice deflection away from the culpability of the oil industry.
The US government is sovereign in its own currency and has exactly as much money as it chooses to create and spend. (Ditto the UK, and that's one thing, at least, to thank Thatcher for: keeping the UK a currency-issuer rather than a currency-user, ie: not Greece.) If the US chooses not to fund retirement for younger generations, that's a political decision, not an economic one.