I'd be really surprised if Disney cut the EMHs. It's a big selling point.
Do we know this to be true? With all of the tracking Disney can now do of guests, I would imagine they now know exactly what percentage of on-site guests actually take advantage on EMH. How many rides, how much food or merchandise purchased. It's then pretty easy to do a cost benefit analysis of keeping the parks open.
As people have pointed out, EMH is a marketing tool. So one would think that perhaps it will be replaced with some other program. Perhaps extended hours for all, but only resort guests get extended hour fast passes. This would retain a perk for resort guests, but also allow for the costs of extended hours to be spread over more guests with more opportunity to spend money on food and merchandise. Or how about EMH everyday. No need for a schedule, parks soft open and close to resort guests and hour early and an hour late. Select rides begin operation early or continue running late on a revolving schedule.
While I have enjoyed EMH on occasion, I have found it frustrating to try to plan visits to specific parks based on EMH. If we are at MK late for fireworks, I really don't want to go to a park early the next morning. The day we arrive, there is never a park with extended hours that night. Etc.
So, if the program goes away without any replacement presumably to save costs, then hopefully it will reduce the annual inflation of prices. If it impacts the amount of resort guests, it just means there might be more promotional discounts and more availability. So a possible lose - win situation.
If it gets replaced with a new program that lets resort guests enjoy extended hour benefits on a more flexible schedule, then win-win.