Not surprised. Housing went up a lot in recent years and it is not affordable for most young people. And if you have to rent, why not rent your parent's?
Housing in the West was basically turned into another pillar of retiree funding. Old people extract tremendous financial gains from younger generations by either a) selling them decrepit real estate at extremely high prices or b) collecting very high rents on buildings that are even older than themselves (even in the US, which is the king of corporate landlording, they are a small minority; most landlords are natural persons, mostly retirees or near-retirees).
It turns out if you do that the living space required to raise the next generation simply becomes inaccessible.
(Another way to look at it - people on new leases will often spend around 30-40% of net income on rent. In most instances this is a direct transfer to a retiree/near-retiree. Taxes, a lot of which also goes towards transfer payments, and other transfer payments to old people, are 40-50% in many countries. Taken together, younger, working people are effectively transferring 2/3rds or more of their gross income to retirees before spending the first cent on themselves. Why would anyone be surprised people are checking out of that system en-masse?)
No matter the system you'd end up with the working age population tending for the children and elderly. I don't think that in it self is a problem. You could argue around implementation details though ...
(Near-)retirees are typically the largest voting bloc and usually the only one experiencing any growth in most of the West. It is unsurprising that they get to set policies that solely benefit them at the expense of everyone else, including those that are yet to be born and those who will never be born because of those policies. And why would they care about the future? Retirees, by revealed preference, don't, and why would they? It's not their future they're destroying. Indeed, they're making quite a nice (short) future for themselves by bleeding societies dry.
It turns out if you do that the living space required to raise the next generation simply becomes inaccessible.
(Another way to look at it - people on new leases will often spend around 30-40% of net income on rent. In most instances this is a direct transfer to a retiree/near-retiree. Taxes, a lot of which also goes towards transfer payments, and other transfer payments to old people, are 40-50% in many countries. Taken together, younger, working people are effectively transferring 2/3rds or more of their gross income to retirees before spending the first cent on themselves. Why would anyone be surprised people are checking out of that system en-masse?)