Oh actually, if you go and read the bill text they link, there is in fact a cap at $10m along with other measures to close up loopholes. Starting at section 138301.
Given the relatively low cap on IRA contributions, it's not directly an issue of income, but rather your access to high-return investments like early-stage stock options.
Of course, someone with lots of investments will have the luxury of just making the highest-payoff ones with their IRA funds.
Independently, in the rest of the bill [1] there are lots of reasonable things like a $10 million IRA cutoff limit.
Presumably meant to address high net worth individuals completely dodging taxation on huge gains by using their IRAs for investments like exercising early-stage stock options.[1]
I kind of wish they'd go with just capping the gains, but would I still say that if I wasn't planning to use mine to "fund" high-return cryptocurrency arbitrages?
https://www.irs.gov/retirement-plans/plan-participant-employ...