As of 2021, a very high income married one-earner household can potentially put away $19.5k/yr pre-tax into a traditional 401(k), $38.5k/yr into a after-tax Roth 401(k) which can be optionally converted to a Roth IRA, plus $6k/yr for both the worker and the spouse into Roth IRAs, plus $7,200/yr into a family HSA (if it's available thru your employer).
That's $19.5k + 38.5k + 6k + 6k + 7.2k = 77.2k tax advantaged. $57.7k of that is not subject to income tax or capital gains upon distribution, as long as you are following the rules. Not too bad.
But a material chunk of the $14M belongs to the government (not available for the individual to spend).
If someone takes out a $2M loan at the age of 58, and retires at 59 (before any of it is paid back), do you think that should be money considered in a retirement calculation?
Also, Capital gains is treated differently than ordinary income.
Your income tax bracket is irrelevant in determining your capital gains rate (at least for now).
Income tax bracket doesn't directly correspond with capital gains brackets, but total income affects the capital gains tax rate.
Unless you know of a way to put $84k/year into a roth account.