You don't seem to get the other half of the advice - earn more money. Get better at making money. If you spend a lifetime to save $100,000, you won't be a millionaire.
The point of a 401k is that it is tax advantaged and the money is there when you get old, when you need it.
I can understand piling money in a bank if there is something you plan to do with it. But piling 100k in a bank when your only plan is "so NOW I am ready to do something with it" is some of the dumbest financial advice I have ever seen. Even if this guy is good at making money, he must be even better at spending it, and the tax man is going to be his biggest payee.
Huh? Assuming this is all after-tax money and isn't earning anything, what would you be paying taxes on exactly?
A bank account is the absolute worst place to park any significant amount of money. The only reason it's better than a mattress is you don't have to worry about the bank catching on fire.
Personally I think a Roth IRA is the better deal from a tax standpoint -- pay taxes on contributions and then you're done. With a long enough time horizon and a little luck those contributions will be dwarfed by earnings, and I would rather pay taxes on the lesser amount.
A savings account earning >=1% interest is a negligible tax burden. What you lose from inflation is far greater than what you pay in taxes. Even so, saying it's "the absolute worst place" to put money is beyond hyperbolic.