They can to some extent, actually... See IRS publication Publication 536, "Net Operating Losses (NOLs) for Individuals, Estates, and Trusts".
> Spend the entirety of your 20s making very little money because you are investing in growth
To actually do the equivalent you would need to spend your 20s _losing_ money. And if you do (in the NOL sense per publication 536) then you can in fact keep rolling the losses forward to offset future income until the losses are exhausted.
Now one issue is that things like medical school tuition are not considered "losses" for individuals. So in that sense there is a definite asymmetry here.
But businesses can't "go back and use all the unused 24% bracket", not least because US federal corporate income tax does not have brackets. What they can do is that _if_ they have negative taxable income (i.e. revenues - deductible expenses is negative) then they can roll the "unused" part of the deduction into future years to offset future revenues, which is exactly how NOL works for individuals. The primary difference between businesses and individuals here is in what counts as "deductible expense". The business definition is much wider in general, not just for purposes of NOL.
> You also can’t deduct the interest on the loans you took to finance that growth.
Well, you can until you start making that $800k/year. And only up to a limit, etc. Just like so many other things in the personal tax code, there's an income phaseout and a cap for student loan interest deductions...