The Netherlands is densely populated. There isn't as much space available compared to most other countries.
Also Amsterdam is the peak of tiny spaces here. Single bedroom 25 m2, with shared toilet/kitchen for sale can cost you €100.000,- easily.
That blackish blob in Europe is the Netherlands.
https://www.sheffield.ac.uk/news/nr/land-cover-atlas-uk-1.74...
It's a political choice, a matter of spatial planning, to live this densly.
I actually just landed at Schiphol on a clear day and you can see the country just has so much sparsely populated areas peaking out the window on approach