And shall we shut down the 401k plans while we were at it? That was an unintended consequence of the obscure subsection (k) of some law and it created a booming retirement saving vehicle.
With the tax code, IRAs and such were always tax breaks and always intended as such to encourage savings. To call them a “loophole” is just hostile political language aimed at harming their beneficiaries and trying to justify breaking the original terms retroactively.
There were never rules that said your IRA can’t be bigger than $X, since there was clearly no intent to punish investment success. Time was when that would have been unAmerican. They had limits for how much you could put in (I remember many many years of $2k max not adjusted for inflation as it is now), and even that was cut down or cut off if your income was too high or you already had a retirement plan at work.
The Roth conversion option was explicitly allowed later, having not been originally, as a way to raise short term revenue projections by encouraging people to pay their taxes sooner in exchange for not paying them later. So instead of getting a lifetime of tax free appreciation that you signed up for and paid extra taxes for, now you could get a lot of that money handed back to you since you invested too well - no tax break going forward and maybe a 10% penalty for being forced to take it out sooner than retirement age.
Sounds more like a 10% IRA confiscation if they do it that way, but don’t worry, for now it’s only $10M and the Evil Rich. Wait til they’re done printing at the Fed and see if $10M buys a nice house…