Your entire post is overgeneralization and dramatizing to prove some poorly thought out hypothesis but this here is the most obvious example. When there is enough choice people change jobs all the time - the demand in my local dev market went through the roof last couple of years for multiple reasons - I see people change 2 jobs within a year, demand all sorts of things - last round of job interviews I did the interviewers spent double the time explaining why their company was a great fit for me instead of actually interviewing me for position - compared to the usual narrative of asking why I fit them.
The situation is pretty much dictated by supply/demand and both sides take advantage. Firing and quitting can have negative implications for both sides, just depends on scenario.
I don't see where shame enters the equation.