This is a very frustrating issue, and hard to overcome. I too train alone, for the most part. I've never been able to find a great training partner. Either they are unreliable, or they are not as serious, etc. When I was in HS I had ONE partner for a few years that was great when we were in the gym, but he often had other things to do and would miss workouts. Other partners would show up but not have the intensity there.
I think, as others have said, everyone has their own goals, motivation levels, schedules, etc. You sound like a committed guy. First it is probably hard to find someone equally as committed - especially among friends who are friends for any reason other than you met them in a gym. Second, if someone works out with you, it probably isn't "fun". Think how hard it is for most people just to get into the routine of working out on the regular. I know it took me a good 4-5 years to finally find my motivation for it. And that's just doing it by myself. If I'm barely finding my motivation - partnering with someone who is committed and not "fun" may not get me too excited.
For instance, my gf sometimes tries to workout with me. I am intense, work hard, and get out. She has trouble pushing the way I do and it upsets her and winds up quitting.
Finding a good training partner can make a world of difference though. I don't think many people become elite on their own. They have partners, coaches, reliable people who help them improve and guide them objectively.
