Tax rates in continental Europe can indeed be steep compared to UK and US. In the Netherlands the top rate is 'only' 52%, not 70%. Most people, especially company owners, pay much less.

Yep. And only the income above ~ €56,491 will be taxed by 52% so your average tax rate will be much lower

Especially since the rent on your mortgage is deductible. Adding to that, expats have extra tax discounts (30% ruling).