I do not think this proposal will advance at this point, or it likely would have been included in the recent ARA legislation. The focus now is shifting to making up lost tax revenue due to Covid and excessive spending.
In addition, lacking a major market crash, this is the type of legislation that is typically done in advance so that custodians do not have to deal with distributions and rollovers as they did last year.
However, the new RMD tables will go into effect in 2022, and RMDs will be lowered in the rough amount of 6%.
Finally, there are many taxpayers who would actually be hurt by concentrating RMDs into fewer years. 3 added years of potential gains with no RMDs will result in larger RMDs when they finally start, or larger IRA balances left to beneficiaries, most of whom will have only 10 years to drain the inherited IRA.