The 757 has a slower approach speed and higher crosswind limit. There is no narrowbody aircraft available today that can match its capabilities on short difficult runways and seat 200 people. The problem is it was designed when jet fuel was 25 cents a gallon. The current narrowbody choices above 150 seats are optimized for fuel economy at cruise. They have smaller wings and higher approach speeds. Their main gear are single axle verses tandom axle on the 757 to save weight. 4 verses 8 tires braking. The last 757’s were built in 2004. Most are approaching 25 years old. They are rapidly being retired. STT as an example was a sea of 757’s 10 years ago seating 190 to 200 people. It’s now heavily A319’s and 737-700’s seating 130 people. Since both STT and SXM don’t have any additional ramp space for more flights the available seats for sale has dropped dramatically leading to higher ticket prices.
Boeing was going to build an all new 757 replacement but the engineers got overruled by the accountants and opted for the cheaper strategy of stretching the 737. That has not gone well for Boeing. There is some discussion at Delta and I believe United to overhauling and life extending small 757 fleets for difficult airports. As the aircraft reach the 25 to 30 year old point the overhual required becomes quiet expensive. It’s literally a complete tear down and rebuild of the airframe. Not sure if the bean counters will approve that expense.