Waist width is definitely not the issue for on3ps, I have jeffery 96s that blow on hard snow and 104 sfbs that are way nicer on hard snow for carving due to the taper and rocker differences. The only advantage a narrower ski that doesnt carve as well will offer is an easier time doing tech rail tricks and faster edge to edge in sketchy situations where there is good grip which isn't something most people are after.
Fatter skis also have more leverage on your knees on hardpack when railing turns and now that im getting older and have some lingering injuries from my youth I can really feel the difference between a 104 ski and something narrower underfoot. Even my fis sl skis hurt my knees less these days then my sfbs just cause the waist is like 40mm narrower even though the fis skis are way more aggressive and I do like twice as many turns every run. An on3p wont really rail turns so you might as well just take the extra float.
Aka at the end of the day on3ps are gonna suck for carving on hard snow so its not surprising the lowest non custom waist width is creeping up especially with all the covid effects on how many skis they can make a season. Its definitely not a brand with skis that are designed for daily use while east coast skiing so they might as well focus production on the skis that have wider appeal/width.