Observing over the decades, ACA has always evolved with the times. If a trip sold out early one year, they'd add additional date(s) the next. If sign-up was light, the trip could and often did get dropped from the organization's offerings.
In addition, the current management is focusing on the 'untoured', evangelizing to the touring curious and potential first-timers. They've started a big short tours and overnighters initiative and are funding under-represented demographic groups.
Maybe, but they always said those routes across the US were their most popular and consistently booked up, but maybe with prices going way up not enough signed up? If a trip was booked they always showed the trip but then said it was booked up for the season.
I went to a bunch of touring places and all the prices have gone way up for all the trips but the cross country unsupported were $14,000 to $27,000! ACA always was the least expensive, and still is, but the prices have gone way up. What's really strange, you can do bike touring in Europe for half the cost that it is in America?!