Animal Kingdom with no Expedition Everest is about a four hour park. With a fully functional A mode yeti, EE gobbles up the time of lots of people who want to ride it over and over again. It's amazing. Without A mode yeti, it's still a good ride, the most popular thing at AK, and the draw (or wienie) that Walt would've said draws the people in. Shutting it down completely would also be an a huge glaring embarrassment. People would know and be constantly reminded that Disney screwed up.
Plus, most people in line probably know no better. It's a good ride in B mode, but it was an amazing ride in A mode. It still attracts thousands of people everyday, and fills their days. Believe me, if EE were to shut down now before Pandora opens, AK attendance would drop dramatically. Disney would be seen as a joke, and that huge mountain of a black eye would be there for all to see.
Again, the tragedy is that a $20 Ace Hardware strobe light is the best replacement they could conjure up. Absolutely 100% insane and lazy that nothing better can be installed given the projection tech that is out there these days.