Even if you can guarantee that your retirement income wouldn't be higher, you can't guarantee that your tax would be lower either. So I'd have both traditional and Roth IRA (e.g., 50/50)
Take a look at any of the Millenials working in any large-city downtown: they spend every single penny they earn, they have no savings; when they get older, either the State will let them starve to death, or taxes will be raised in order to take care of them.
I don't think the former is politically possible, so taxes will have to go up.
Meanwhile, the same spendthrifts are by-and-large refusing to have children early, which means that there will be fewer workers to pay those taxes.
That means that there will be tremendous political pressure to raid 401(k) plans and IRAs. I actually believe it's even odds whether Roths will end up taxed one way or another (perhaps with 'withdrawal fees' or some form of Social Security clawback or something): it'll be too much money for the State to leave alone.
The advantage of a 401K over the Roth is that since both can be raided, at least with the 401K your money is being taxed only on the way out. With the Roth you are being taxed on the way in for sure, and you run the risk of it being taxed on the way out as well.
Judging from the past my guess would be that we wont see something as obvious as a penalty or a fee. Instead what you may see is a more aggressive required minimum distribution schedule. Perhaps you could see the date of penalty free withdrawal pushed back from 59.5 to 65 or 67 years of age. Means testing of social security benefits has been mentioned before. If that gets put in place, and you fail the means test for social security, they will have effectively taxed you more your entire working life.
Or we could just continue doing what we are currently, and just keep piling up the debt :) No tax increase or Roth/401k raids needed.
Don't forget the more politically expedient (and in my view most likely) choice: Print money to pay for it, causing inflation, which is essentially a silent tax on everyone with money.
This is an assumption I'm working under, but I've thought about it for a more normal case as well.
Still, the usual advice for saving for a normal retirement is 10%-15%, and you only have to break $185k before a 401(k) doesn't cover even the low end of that.
Also, if you're making that much, even if you want to retire early, the normal % rules of thumb don't necessarily apply, assuming you want to live a normal middle-class life in retirement. You should run the numbers on http://firecalc.com, you will find if you live frugally making that much and contribute the max you can easily retire in under 20 years with a >90% chance of success. If you want to retire to the high life you will either have to contribute more than normal(and invest well/be lucky) or work longer, no matter your income.
Edit: I will say that there is a potentially significant disadvantage, especially for high earners, in having a lot of your net worth tied up in a 401k. That is required minimum distributions, essentially forcing you to take out a certain percentage of your account balance when you reach certain age thresholds. You can somewhat easily get around this by rolling over into a Roth IRA(backdoor Roth), but that could offset many of the tax advantages of the 401k in the first place if you have significant traditional IRA holdings[1]. This is mostly deleterious if you are planning on bequeathing an estate in a tax-advantaged way, but you may be able to get around it with a irrevocable trust. Consult a fiduciary, this is not financial advice.
1. https://www.bogleheads.org/wiki/Backdoor_Roth_IRA#Caution