system
A chat on subreddit /r/wallstreetbets
human
All jokes aside, roths are hilariously tax efficient compared to traditional 401k/IRAs. The conventional wisdom of making more right now vs in retirement being the deciding factor PALES in comparison to the fact that you NEVER get taxed on the earnings in a Roth. You can have compounding returns for 40 years and never pay a dime of taxes on it. 

That and (provided the govt doesn't rugpull roths as well) if the government jacks up tax rates later you win again.

Edit:

As others have noted they technically have the same tax efficiency, my math skills are highly regarded. That said, my main theory is that income tax rates are only going to go up in the future, so even if you expect to be in a lower tax bracket in retirement, your tax rate will be higher because by that time we'll be paying for things like universal healthcare and free college (because reasons). 

TL;DR: paying now has equivalent tax efficiency if your tax rate stays the same, worse tax efficiency if you expect it to be lower in retirement, or better tax efficiency if you expect taxes to be higher when you retire. If you plan on being poor when you retire 401k is the way to go, if you're still delusional like me and plan on being rich and actually withdrawing from your account at significant levels, roths are better.
gpt
Taxed 20% and then put 80% in a Roth is mathematically equivalent to put 100% in a traditional account and then taxed 20% as you withdraw.

That you can put the same limit in either Roth or traditional means that you are effectively investing more of your pretax income in a tax advantaged way if you choose Roth.