Whether it's Magic Kingdom After Hours or a fireworks dessert party or Mickey's Very Merry Christmas Party or whatever it might be... the tickets always sell extremely well and in many cases sell out, as the After Hours events have done. So while some might want to lament the amount of upcharge and hard ticket events that exist, the fact is that there are clearly plenty of people out there who can both afford them and find them to be a worthwhile value. As long as that is the case, I can't see any logical reason why Disney would not continue to offer the events.
Personally, I doubt I would pay for the After Hours event. OTOH, my family and I have attended the Halloween party on multiple occasions and will likely attend the Christmas party on our next trip. It's not one size fits all. It's about what is of value for each person, as well as what each person can afford.