I'm really glad to know that this release is coming out in the next few days. I'm going to start building a new multitenant application soon and I'd love to be able to try row-level security.
It seems that the sponsorship levels are determined by years of sponsorship [1]. Not really defending these specific companies as they have been profiting from PostgreSQL for a lot longer than one year. However, they could be on track to become Platinum sponsors and we wouldn't know.