It's in Kabam's interests to do this. I'm a full time suicide user, I avoid ranking up champs that are not suicide friendly. If I could switch masteries easily, I would consider ranking up far more champs.
I believe on the last dev blog they put out, they said that mastery changes were coming 2022. I could be wrong though.
My Magic Crystal Ball of Dev-ination reports, "We know it's really wanted but we're not quite sure what we can , could, or should do."
I wouldn't be opposed to them bundling the unit cost into the sigil for unlimited changes, I don't want them to lose out on their $$$'s