Hmmm... those were two interesting posts. [That have now been edited]
I climb solo because I have to. I climb solo because sometimes I'm left to work alone by my customer (contract climbing). I climb alone because I like it.
On pruning jobs and some takedowns I need to make every penny of what i charge because I'm working to re-establish myself after losing my life's savings... I can't afford a ground man just to watch my safety while i clean crowns.
Plenty of times I've been working contract and my employer takes off to do something else like bid jobs or something. It just happens that way, I never thought about it as a problem.
I like climbing alone, I have since I was 18 when I got into soloing short 50' rock routes on my home cliffs. It was an exercise in keeping a cool head... extremely rewarding.
When I climb trees alone I'm always roped, always careful and methodical... maybe I'm jaded but it doesn't seem dangerous at all compared to driving or riding a bicycle around here.
When I got into tree work I was pretty amazed at how safety oriented it is, triple locking biners, backed up figure eights and ascenders... it was a lot different than climbing rock where a single screw lock biner was your harness tie in and rapping on old fixed ropes with a figure eight were standard things... lead falls on 9/16" nylon tape with plain caribiners. I gotta say I like the ANSI Z and I follow it pretty close... it makes climbing trees a completely different discipline than rock... barring a major lapse in judgment, falling seems pretty unlikely in trees... being struck or cut are the risks I worry about now.
Everything has risk associated with it. Managing that risk is how we stay safe. Fear is a great motivator and teacher of managed risk. If you pay attention to it, let it guide you without being overwhelmed by it and learn from it... you can consistently do dangerous things safely. I don't want to get hurt... hell, I can't afford it. I don't take risks without KNOWING I can manage them.
I don't think solo climbing is either balls out or anti-social... it's personal. If you want to be balls out, don't use a rope. If you get hurt climbing it doesn't matter if someone is there or not, it's bad for the individual and it's bad for the community.[There was a post stating that climbing solo is anti-social and peculiar to Americans, it's been edited]
If you don't want to climb solo I respect that totally... having kids to think about is the best possible reason there is. When my kids were young I backed off of high risk sport, getting into climbing trees now that they're getting older has filled an empty space in my life. It's also cool because they never knew their dad when he was a wild man... now they're getting some idea of who I used to be. I like doing dangerous things safely, it's one of the most personally rewarding things I know.