It was way too reliant on SOS and too easy to manipulate through clever scheduling. The selection committee understood how terrible RPI was and didn't actually use it very much outside of it being a way to evaluate "good wins" and "bad losses". There were teams ranked in the 60s and 70s in the RPI getting in with teams in the 30s and 40s being left out in the past. It's expected that will be a lot loss likely with using NET instead. This year's BYU team would likely have pretty close to a 0% shot at the NCAA tournament anyways even if they were still using RPI.