this would essentially mean a transfer of wealth from the masses sending remittances to a few HFT traders.
Compared to a frictionless world, this is sub optimal. But as you and the article established, there are frictions that currently result in a tranfer of wealth at a 6% rate of transfer volume which could very well be greater than the future equilibrium you posit.
I think that there are options that could be implemented at scale faster and simpler compared to crypto token exchanges. But any individual current getting hit with high transfer fees could benefit immediately if they know about and learn how to use something like monero.