While I concur with the views above that time to first solo is a rather useless statistic, it is interesting to look at it from the student's comfort viewpoint. (I choose to ignore the integrity aspects of commercial greed here).
Co-incidentally, I went solo very early. The specific number of hours is not important and, I guess, the now long dead instructor was quite comfortable with me as I was his first solo after a 20 year airline break from his previous instructing jobs. It is illustrative to note that, of our course of about 10 RAAF ATC flying scholarship folk, all but one went solo in well under 10 hours .. perhaps this particular instructor put some emphasis on rapid progress. Certainly he kept the pressure on .. I have never since been under such intense pressure to learn as in that particular course ... in my view, the fellow was a superb passer-on of things to students .. I guess the occasional belt over the back of the head with a rolled-up newspaper helped maintain focus as well ...
However, the interesting question is along the lines of "did I have much of a clue about what I was doing when I got launched off by myself ?"
The facile answer is "yes", otherwise Cec wouldn't have sent me off.
The considered answer after many more years in the Industry is that I didn't have a clue what was going on. I could push and pull the stick and find the runway, sure, but I thank my lucky stars nothing choose to go wrong.
Sober reflection suggests to me that I would have sent me off a couple of hours further along the learning curve ?