You can rent, but that's money wasted. The longer you rent, the longer you didn't invest. Also rents are higher than mortgage payments, making it worse.
I own today, but I'm well ahead of most of my peers that bought houses right out of college.
As for investing: you invested what you had left after rent, but you didn't invest what you paid in rent. With a mortgage, you are investing the mortage payment minus interest, and you can still invest what you have left.
I'm observing rents way, way below mortgages, but it's very location dependent.
When making decisions about where to put my money, I stopped worrying about what other people are going to do and are doing, what the market might do, etc, and instead think what makes _sense_ for me to do. If some expense makes sense for me, offers good value, etc, independent of attempting to prognosticate the future, it probably does for others as well and the investment will probably work out fine. If it doesn't, it doesn't matter, it still made sense for me to do it.
For me, this has meant buying a house when lots of my peers were running scared at what turned out to be the bottom of the housing market, selling one recently, and renting for the moment. In each case, this was just the cheaper and 'sensible' approach. I think people overcomplicated this stuff.
How does the math work in the Netherlands?
Interest rates used to be lower so the mortgage used to be much cheaper.
But in a different financial environment, maybe a few years from now, your expectations might be different and the math works out differently
A bit odd that you talk about liquidity. The house itself isn't liquid, but you finance it so you don't need a huge liquidity up front. Also, rents paid are no longer liquid to you either.
A mortgage ends one day. Rents do not.
House prices increase 20% year on year in Amsterdam. Even during the 2008 financial crisis did they barely drop in value.
Just wait until you see how much is wasted in a 30 year loan. These decisions often comes down to life style.