Probably. If you look at the sensitivity of passenger traffic to travel time, the graph is roughly a logistic curve with the inflection point around the 3 hour mark. On a 40-hour trip, the number of people you'd add to the train by cutting out 4 hours of stops is probably on the order of 10-100 people per trip. If those stations collectively serve more than that number of people, then you're losing people by cutting those stops.

It's a question of demand really and maybe driven by a chicken and egg problem. Trains are slow and expensive so people prefer to fly leading to a lack of demand to support both a slow every stop train and an express point to point train. Also I imagine prices would increase on an express train compared to current trains because it will be picking up less passengers from those intermediate stations. It's tough to setup a lot of different trains because tracks are afaik one per direction in most locations and lines so you're very harshly limited on the scheduling side of things.

I don't know about this route in particular, but Amtrak generally runs on freight lines. It's quite possible that the time lost to stopping to pick up a couple passengers is dwarfed by the time spent sitting on a siding waiting for freight trains to pass (I've spent many hours of my life here).