Generally, sororities end in failure. Don't feel bad, I too have quit. Nothing against sorority keepers, but after mine failed I realized that they will have a better life on their own, unless in a large tank. If kept as babies possibly, but still, it is like living your entire life in a house bickering with your sisters. You will be stressed and not as happy.
I have no doubt others, by whatever successful formula they have discovered - large numbers, related fish, starting with babies, etc - are keeping healthy, contented, sorority tanks and I commend them whole-heartedly. It does take an extra ordinary effort though and I found I didn't have all the same "qualities" some of the better, more experienced Betta people obviously enjoy.
I went into this feeling good about the endeavor, thinking I was once again about to improve the living conditions of a bunch of fish that were in need of rescue from a bad situation (the store). When I failed, which I almost never do, the immediate, knee-jerk response was to blame the fish. Being as I was reporting on the situation in real time, something I am relatively new at doing, I ran to the computer to air out my frustrations in the heat of the moment without first thinking it through. This was a mistake and I said some things I shouldn't have. And of course, once something is on the web, you can't take it back. All I can do now is take the hate, ask for forgiveness, and move on.
Bettas are wonderful pets. I have kept at least 5 males till they died of natural causes at ripe old ages and thoroughly enjoyed them. I have one now in his own 5 gallon heated and filtered tank. I always thought I would get around to breeding some and raising the babies. This experiment, if it had been successful, would have eventually lead to that end.
I am not against Bettas. I am just unhappy about having to face the truth that one is all I will ever be able to care for at a time. You see, I have a thing about keeping all my fish in heated, filtered tanks. And I just don't have the space to provide this to more than a couple of solitary Bettas. Though I would love to keep dozens, I will not resort to bowls and vases.