Yes. People travel. They don't always travel because they want to, but because there is a family gathering, there is important business to take care of at the other end. Everyone shops for the "lowest" air fare.
I contend that people would pay up for "all premium" air fare. Just the fare, roomy seats, no extra charges for carry-ons, checked bags, and to somehow make the airport experience more pleasant.
You have a regular route ... HPN-RSW. Two of the richest enclaves around .. Regional Southwest Florida to Westchester County. It used to be a fairly comfortable flight. Westchester Airport is a blight and there is little you can do to improve it save trying to charge me $60 to check my walker in luggage. RSW is not an unpleasant experience save getting on the plane and cramming a small computer case under the seat in front of me and squishing into my "extra room" seat that I paid up for .
I contend that removing a few rows of seats, adding 10% to the price, you could make money on your own without trying to acquire a garbage airline like Spirit. My son's experience with Spirit as the "cheapest flight" he got surcharges for every bag, checked or not, even seat choice (so he could sit with his wife}. He now flies American when he comes.
I recall a trip several years ago where the pilot came on the horn as we were landing "We know you had a choice, Thank you for flying United". Long story short I took the same trip several more times on Delta. One trip I was grounded in Atlanta overnight once (storms). I got on an early flight to my destination on standby, and my luggage arrived with me!
All airlines seem to have lost the focus on CUSTOMER. And why people fly. To desperately cling to airfares from ten years ago with stupid surcharges is a ridiculous business plan. Give service, you will get paid.