Except that u put up requirements and get to scan the persons loadout and level before they join do it's not random like matchmaking would be. Again the only people who would do matchmaking (without serious incentive anyway) would be the inexperienced and under leveled. Now if u put 6 inexperienced and under leveled people in a raid together what kind of experience would they have? Guided games had a 1-3 hour wait time for solos so that gives u an idea of how popular it was. The only way to increase the amount of raiders is to convince the "toxic" raiders to help and teach them. Since the normal way to do that is to be friendly and fun, I'd assume that most of the solos are either not fun to play with or not social. Since they aren't the only way raiders will tolerate them is to bribe them with extra high level gear or bring able to directly select a specific armor piece or weapon for easier god roll farming. If you don't do it that way raid matchmaking will die bc it will be a waste of money for bungie.