I'm not sure what you mean by having all this time?
One person did stand up to him and they were blamed and made to look like the bad guy. Many of us, me included, I am sorry to say i remained neutral and didn't support the person who had come to their senses.
Some of us were aghast at how far things had gone that we were left dumbfounded and didn't react in a timely fashion. Others are now so used to the behavior that they see it as normal and think it is ok. They still cannot understand my frustration.
I told one person that I would not be letting uninvited friend of person into event and they said that would be rude to the person who didn't know not to attend, he was invited by someone after all, and it is only one person, we can make it work. Excuses which enable.
In the end this is likely to break up the group because some people won't stop inviting him, others try to remain neutral which enables the behavior and some of us may leave the group if we cannot stop it.
I think you're right here - the past behaviour of the group gives a very strong clue about their future behaviour.
You've got someone who has flagrantly overstepped anything remotely resembling reasonable boundaries to the point of deliberate and unambiguous theft of money and possessions. The reaction of the social group has been to enable him, to either turn on anyone who objects, or stand out of the way and say nothing.
What you *can* do, in the short term, is refuse to put up with his garbage. Refuse to have him in your home. If you're hosting, you can send out the invitations to everyone but him, and turn him away at the door. Be prepared for a scene, though. If he needs a ride, don't give one. If he tries to forcibly stay over at your house because he 'doesn't have a ride', you tell him to get off your property or you're calling the police, and you lock the doors when he's out. If he shows up without cash, and people are pitching in, you say "Oh, I don't have any extra money (stock your purse with exact change in advance). If you're at an event he is attending, take a purse with a single compartment and a zipper and lock it with a combination travel lock so he can't get in.
Have social events, and invite the reasonable people in the group - the ones who have objected to his behaviour, or who dislike it haven't objected.
But I think you're right - this behaviour is so ingrained in your group that the best solution is to let the group break up, and re-assemble a group of genuine friends from the wreckage.