They won't....
The FCC had a poor record of collecting fines, even back when they were a few thousand dollars... and the US Justice Department, who would have been their primary means of collection action, had better things to do...
Millions?? This is a CROCK!
Even if they had the means, which they probably don't, they would hang onto their money and skip town!
They will probably fold the station, and restart as another name and frequncy---
but if they are selling advertising and actually making money off their operation,
they may continue for a little longer--- using remote unmanned sites,
where there is no one who can be arrested....