> If the problem is the lack of housing.

It's not. I don't have statistics for the Netherlands ready, but I would bet that they have more housing units than households. In the US, there's 1.1 housing unit per household.

> Why wouldn't building more be a solution?

Because it's not a housing problem. It's a problem with housing near dense city cores in an ever-dwindling number of cities.

Economic forces concentrate people into dense areas: dense population provides a larger talent pool for employers, so companies with offices in dense city cores have a long-term competitive advantage. This in turn attracts more people. Rinse, wash, repeat.

The solution is to recognize the externalities and properly manage them. For example: cap&trade/tax the dense office space, give tax incentives for remote work, provide tax holidays for people in sparse areas, and so on.