Everyone was already expecting it to be released any day, the beta didn't just leak out of nowhere while he was moths away. Comex had already put up a second teaser and made twitter comments like "just need a bootstrap..." and "running out of bugs to fix" without ever saying a word about holding it back for iOS 5.
If Comex says he was going to hold it back for months (and just decided not to tell the thousands of people waiting on it) then I'll believe it, but all signs were that he was going to release it well before iOS 5 and thus it would be fixed anyway.
Hell if he was going to hold back that long, a whole lot of people probably would thank the leak for getting it released now. It's not like it's automatic that the iPhone 5 and iOS 5 will take 4 months to jailbreak. Wont they get far more developer interest due to the many times larger userbase?