With Disney World getting more expensive every year, and sadly with every price hike, there are people at the bottom of the spectrum getting priced out. This means people have to save harder, or make more money. And as Disney's strategy is to reduce crowds by increasing prices they are obviously targeting guests who have more disposable income, and this leads to the opportunity for Disney to make more money from guests with extra hard-ticket events, like "After Hours".
For us Brits, there are other forces—some outside of Disney's control—which makes Disney World more expensive for us. That includes flight prices and exchange rates. People hunt all year round for bargain flight prices, and are willing to put up with stops and using non-British airlines to reduce costs.
These tickets, at the time of writing, cost around $125+tax per person for 3 hours of quiet park access (and unlimited bottled drinks, ice cream & popcorn). I cannot find any concrete numbers on how many tickets are sold each night, but it's a lot less than the Halloween and Christmas parties (which I'll get to). When we went in September 2018, I paid ~$250 for the both of us to spend the evening at Magic Kingdom. To compare, a 14 day Ultimate Disney World ticket costs around £400 ($500) - which is bonkers when you think about it.
However, this was the line for Peter Pan.
And this was the waiting room for Haunted Mansion.
I've found that people get confused between these "After Hours" events and "Extra Magic Hours". I think Disney needs to call these extra events something else, because it leads to the frustration of people thinking it's included in their hotel stay—which is sort of sounds like it should. People have argued it should be included, and suggesting that Disney should open up the parks a little more for hotel guests, as Extra Magic Hours isn't much benefit anymore as it's just as busy as the rest of the day. However, Disney is a business and has no intention of leaving money on the table. Not to mention the fact that opening these parks up for extra time costs a lot of extra money, and that simply won't be paid for out the Disney's profits.
I personally have no issue with these after hour events, so long as:
Extra Magic Hours at a minimum does not go away
It does not interfere with what is already offered on an already expensive Disney World holiday
Most importantly, they don't ruin it by overselling tickets like they now do with the Halloween and Christmas parties
$125 for 3 hours is no small amount of money, but there is no other way to experience the parks this empty, and while I think the event is generally worth it, the price can get out of control if you're paying for a whole family.
Time is money in Disney World. You could spend 3 hours in queues throughout day, or you could pay the extra $125 and use those three hours doing something else rather than queuing, and enjoy a quiet park in the evening. It's down to whether that is worth $125 for you.