Any relinquishing/wrangling over rights to spectrum, per conuntry, are decided in regular but infrequent international meetings of the ITU assembly. I thought it was every 15 years or something......
Unlike land rights granted in homesteading, it's not use it or lose it.
You're still protected, per country to rights of use of the spectrum, even if you move your commercial services out of that
"band", which was a "range" which came to be defined by the physical combination of a physical inducatance and capacitance, without switching ranges. That's mostly why the MW and PM "band is the range they are.
The concept of a "band" is somewhat obsolete as radios seldon include proper physical TRF tuning components anymore.
Someone must know when the next ITU meeting is, but I'd expect no change on protections.