Two big recent reasons for the shortage are retirees and reduced immigration, and the follow on effects of those. For instance, the people you are wondering abo

Two big recent reasons for the shortage are retirees and reduced immigration, and the follow on effects of those. For instance, the people you are wondering about that "sit at home" are probably moving in with a relative and helping them. And there's a fair chance that relative retired earlier than planned, or was negatively impacted by covid, or both. Covid hit the old primarily, but that age group was helping out with families and communities, and now they need someone to help them. And a longer term effect that has been going on has been a general reduction in working age males in the workforce. That one is more complex and worrisome. There's some recent research about them if you google for it.