Are you familiar with our buyback program?
You can learn more about it here: https://www.sophiatx.com/what-is-sophiatx-buyback-and-why-participate
Trust me, they won't remove even 50% of ERC20 from circulation, because it is an opt-in solution (just like everything in blockchain). The best alternative was to let ERC-20 tokens become deprecated tokens. That would have been much easier to do and would resemble to an opt-out solution (the original plan).
I guess you have a point on that matter but I was also thinking if a simple token swap with 1:1 ratio had been implemented then it could have achieve same results also. Imho.