That’s not quite right. They can take it if they conclude you will not meet the target. Ups and downs on the way there are totally fine under the rules.
Starlink can scale dramatically just by launching new satellites. The FCC is keen on stopping that too, refusing to approve all of Starlink’s satellite launch proposals and instead making them slow walk their growth.
In addition to hating Musk, the White House thinks fiber to the home is like rural electrification. Starlink, by providing very much good-enough universal service (though they can scale up to gigabit speeds, it’s just a matter of how many satellites they have), is threatening to undermine political support for spending money on fiber buildouts.