"... when I do trips with others I prefer to go with people who also feel comfortable doing solo trips."
I never thought of it that way - that's a good way of looking at it.
I haven't had any time I wished I hadn't gone solo (I don't have too much solo experience though).
I do empathize with those who see less liability in solo hiking. Last Fall, a couple buddies & I had a Fish Creek, Az hike planned. There's no trail, really, mostly navigating rocks. Anyway, there were some last minute additions to the group. One of them was a teenager and showed-up in *skate shoes*. Flat bottom, zero traction, may as well hike on marbles skate shoes. They weren't even tied. I'm thinking, this kid is coming home a walking scab. Neither did he have a pack, jacket, hat, sunscreen, anything - not even a water bottle.
I had an extra pair of Montrails in my truck (actually wondered whether they'd be just as bad for being too grippy) - he tries them on, likes them, & I hand him a water bottle.
No more than *5 minutes* into our hike, he takes a flying leap off a boulder, lands wrong (weird, right?) and twists his ankle. It swells up to about twice its original size. Turns out, he'd torn a ligament in his ankle & chipped off a piece of bone.
The conversation afterwards begins with, "Okay - new rule ...."