If we are talking theoretically, then yes, I agree that CUTE gates *should* have a use requirement, and an airline should not be permitted to squat on gates. But, at T1, only the gates themselves will be CUTE, and there will still be airline-specific leaseholds (for which United's space is substantial), and gates allocated to air carriers on a preferential-use basis. The use requirement on the T1 gates is going to be lower than most would expect (something like average of 3 daily turns).
My discussion on this topic is aimed at the idea the Port Authority will be allocating T1 gates principally on the basis of capacity ratios in the post-COVID environment, especially Summer 2020, which is nonsensical. This is an aberration, and while it will take time to get back to 100%, we aren't going to see United suddenly pushed out of T1 because of a temporary reduction in flying necessitated by the pandemic. No chance, and, as I mentioned, most of those gate allocation issues have already been agreed upon, at least in principle.
The other notion, generally unsupported by evidence, is that United squats on gates at EWR, exclusive or not. During normal times, United is usually between 5 and 6 departures per gate, per day, some gates more than others, reflective of the regional/mainline narrow/mainline wide/international arrival mix. That means its usage rate is generally better than DL at JFK (more comparable operation) but not as much as DL at LGA (higher-frequency, smaller aircraft), and several-fold better than AA at JFK. It's roughly equivalent to B6 at JFK T5.
AA allocates space to other carriers in T8 at its discretion, as it is under an exclusive-use arrangement for that terminal, and while T4 is technically CUTE, virtually all DL gates at T4 are at least preferential-use, and some exclusive. CUTE gates are not the free-for-all you seem to think they are, though. If the space is already assigned to an airline, it is incumbent on the airline to maintain a service level for that gate/time to remain preferential or exclusive. Generally, in the case of the NY airports, these are reviewed at long intervals (not month-to-month) and are often part of the horse-trading between airlines and the Port (e.g., part of a negotiation for tenant projects, improvements, capital investments made by an airline, etc.). In other words, it's not considered in a vacuum.
Again, if the gates are not being used at the time, they should be open for other carriers to use, because they are CUTE gates. Sure, most of the gates will have preferred use, but if they are not being used at that moment. You keep bringing up pre-COVID, but we are not talking about pre-COVID. This is about what things look like after COVID. UA will have a much reduced presence for a while due to lack of business demand. Unless it chose to not use T-C and just use T-1 gates when it opens. I'm not even sure how it can do that since it won't be the first to move into T-1, there will be many empty T-1 gates that other airlines can use.
And once other airlines like B6 and NK add up to a certain number of flights, they are not going to be forced to cut back on that because now UA is ready to have more flights. Those gates are not exclusive usage gates. Even if they have preferential access to a carrier. If that carrier is not using it at that moment, it should be available of other carriers to use. That's how CUTE gates work.
CUTE gates by definition are not exclusive.
Anyways, don't think we will agree here, so I will move on.
Which is the reason DL has only scheduled in 75 flights a day in August at LGA (there will be another cut later). UA faces the same problem at EWR that DL has a at LGA. .
The big difference between UA @ EWR and DL @ LGA/JFK is that DL controls slots and new competitors that didn't have service before can't just come in and add flights and threaten DL's market share. DL can sit back and add back flights when it fits their timetable as long as they're not forced to use or lose their slots.
United faces the dilemma that there there are other carriers that are in a position to act faster, with less risk, and can literally walk right in the front door at EWR and add flights where they wish and there's nothing UA can do about it.
That's fair, but UA is also committed to lowering its cash burn. That's not going to happen if it keeps flying empty planes from EWR to nearby business markets. UA will be smaller for a while at EWR whether people like it or not. I think it's great, since I live next to EWR and like more choices. I had resigned myself to flying only *A for a while.
As for DL, I think they might need to get ready to add a lot of flights to LGA, because all the LCCs are eager for the slot waivers to be over. At this point, looks like Jetblue will be running close to enough flights at JFK by December to meet slot usage requirements. No other LCCs are in risk of losing any slots from ending slot waivers.