I firmly believe that keeping non-free and contrib until such time as ALL ofthe needs of our users can be met from main is a good thing.
As you write it, this is an unreasonable demand: who judges it? I suggest that there are some who will never accept that alternatives to non-free packages meet all the needs of our users until everything is in main. If you are willing to let consensus decide, then the converse "drop" proposal will stand or fall accordingly and this serves little purpose.
However, you "second this proposal" rather than "second this amendment"? I am truly confused about what this proposal is. We have the OP's beliefs about what is best, but not a clear statement whether he actually is proposing afresh or amending the "drop"!
-- MJR/slef My Opinion Only and possibly not of any group I know.