I really believe that under the ancien regime any service UA offered that was above the norm had to be monetized or cut. Charging for channel 9, while attractive to them, would be legally problematic as the "talent", the pilots, were not going to be given a cut. So they decide to abandon it in a similar fashion as Global First.
My conspiracy theory for today.....
As facetious as this sounds, I bet it is completely in line with past management's approach to running an airline, absolutely no sense of customer priority or service and blind adherence to cost reduction of anything.