Financial portfolio theory has the idea that owning too much of a particular stock is bad as it exposes you to greater company-specific risk, which unlike systemic risk is not generally compensated for by higher returns (assuming investors are demanding proper risk premiums etc.) This leaves room for a particular kind of human error: you have to sell things which are doing well, as they come to represent a greater proportion of your portfolio that is optimal. This is emotionally difficult.

Societally, we have the same kind of bias. One of the influences on the 2008 Great Recession was a view that home ownership has been good for most home owners, therefore we should incentivize home ownership. Clearly home ownership isn't the only route to good living situations - Germany is fine with much lower rates - and perhaps the conclusion should have been "home owners are doing fine, let's incenticize rentals" or some other option. It's much easier to reinforce something that is going well, even if in that action you are taking on significantly more risk for the future.

On a personal level, this feels true about careers too. The most direct way to greater returns for people with white collar jobs in large companies is, generally, to do well at their job and get promotions or other opportunities. This encourages building up localized skill sets, as differentiated from more market-available skills. This approach brings with it a risk though - you, as an individual, are exposed heavily to your company’s risk profile. Someone who moves around a little more may take on more earnings risk (they might not perform as well at the new firm), but increases their resilience in case of specific company failure.

I remember hearing a story from a friend about an ex-Nokia software developer coming to them after the old Nokia software teams imploded, proud and certain that their accomplishments (which were notable) at Nokia would land them any job they picked. They quickly discovering that the needs the market had were quite different than the skills they could easily demonstrate, leading to a long and somewhat painful sounding job search.