That sounds really weird. In Germany an apartment that rents for about €1000 would sell for €400,000 or so, which means a mortgage would cost 2 to 3 times more (with a 20% down-payment). This is with a 2% interest rate.

How does the math work in the Netherlands?

An apartment that's worth about €400,000 rents for about €1,550. The equivalent mortgage with 3.85% interest is €1875, but becomes about €1426 after tax breaks. The 10% down payment can and often is financed too. This leaves about €10,000 of notary fees and taxes that you have to pay yourself.

Interest rates used to be lower so the mortgage used to be much cheaper.

If the real estate market is near a local maximum, then rent is still a better deal, for now, with your numbers. Upkeep, hoa fees, insurance on an apartment very likely sum to more than €124/mo. That said, of course, if the real estate market is still going to grow by a significant percent, and you time selling correctly, then you could make money by owning.