"The company behind Postgresql" is a misleading and untruthful (I hope this word actually exists) statement. GreatBridge was not _THE_ company behind PostgreSQL. It was _one_ of the companies. pgsql inc. is here, and of course, Red Hat.
The project had a (fast-paced) life of its own much before GreatBridge came along, and it will continue so. We're all sad to see GreatBridge go, but as Ben said, the economy is just hard on start-ups right now.