You are mistaken. Currently, the higher income you have here, the higher tax rate you have, where the highest tax rate on income sits at 47%, which you get hit by when your income is above 300K/year. People between 60K and 300K sits at 45%.
And then there are regional differences, someone in Andalucía don't pay the same amount of taxes as someone who lives in Catalunya for example, where the top tax rate is 50%.
Even taking into account other taxes we have, you still end up paying more in taxes the more you earn, unless you start engaging in schemes to lessen your tax burden, obviously. Although the social security is capped, so it does increase slower once you go beyond the cap, but it doesn't start regressing which your comment hinted at.
Edit: important to note that the tax rates are all marginal tax rates, maybe that was a bit unclear.
This is basically inviting your best and brightest to move to the US and other low tax countries.
If you're in tech, you'll want to move to California, where you'll end up paying around 50% marginal, which is much the same as lots of Western Europe. So yeah, you'll make more money but you won't get significantly lower tax rates.