I don't think "rebuy everything" is accurate, as the problem is that the PS4 hardware can't really emulate/run PS3 games since it is a different architecture. You couldn't rebuy the games because they wouldn't work on the system.
A follow up to this news I read clarified that future "streaming" services may allow access to much of the current PS3/PSN library, but whether or not you'd have to rebuy those compatible games that A) can be streamed and B) are currently tied to your account is yet unknown.

