Current organizer of Data Community DC here. It's a lot of work to get a sponsor, and they tend to churn after a year or two when the individual advocate moves on.
The best sponsors know the value of long term community engagement. Bad sponsors are more transactional, and want to really see the short term value they get.
Can you elaborate on what you mean? In my experience running meetups, sponsoring is an expensive and thankless activity akin to a donation