I understan your point of view. I wouldd simply point out that other forms of this have popped up on E, it's not an uncommon element for players to be put off by the amount of drop rates in group games, nevermindsolo-games. I think we can all say that we have been dropped for reasons that range from partners who simpy decide that it's not going the way that they wanted and didn't want to work on it (My personal peeve) to RL just gets in the way. I've seen a lot of people tell me that they won't play with me because I haven't agreed to this or taken that oath... agreed to this philosophy or that set of guidelines. 90% of the time, these things are the same as those that I've played by for 30 years now, both in table-top, LARP, Email Forums an Messengers. Most of them are common sense.
Sadly, they are not a remedy to the problem. Maturity has something to do with it, as does laziness and simple disinterest. It drives me nuts to spend weeks in PM to work out a storyline and the game die within a couple of weeks. People get a little miffed at me because I want to spend those weeks in prep time for a story... it lets me have some idea if the player is committted to communication and actually wants to write with me. It also helps me to learn if the person and I are actually able to craft a game that both of us wants to play. Just a few ays ago, someone and I decided that we couldn't partner on a story concept because what we wanted was too far apart. That happens and no huge issue.
Anyway,As inticing as the league idea may seem to you, I have to tell you, it is very unlikely to work. People can join and you may fin a few who will follow the reasons behind it, but in time, you'll find that it's little different than the Oath FOOf The Drake. Everyone swears to it, but it's meaningless as a means of establishing a pool of reliable payers.
The only thing that I've foun that really works... most of the time... is to just vet anyone who wants to play. Look at their posting history, talk to people and find out if they meet your requirements. If they do, great. If not, well, you know what you have to work with.
In general, I agree with most of what you said. If I join a game, I intend to be in it for the long haul. Usually, I outlive the game... and know who not to play with as a result. If the game becomes something that I don't want to be involved with, or becomes something other than what was avertised, I'll talk to the GM an see if it can be worked out, but if not, I'll explain myself in OOC and apologize for my leaving. Ultimately though, RL must come first and if I can't get a post out on a regular schedule, I'll try to let someone know. But, if RL is telling me to deal with it, then there is little than I can do about it but try.