They keep re-issuing and re-re-issuing and re-re-re-re-issuing kits for two simple reasons. One, they're cheap to do. The tooling was paid for long ago, so the cost to put out a reissued kit is far less than to tool up a new kit. And two... people keep buying them! It's our own fault. If model kit buyers would stop buying the old reissues, the kit makers would stop reissuing them and put more effort into creating new kits. But as long as people keep buying all the old kits being cranked out, the model companies have less incentive to invest in new kits. By continuing to buy all of these old, lousy kits, we are causing the problem of the never-ending parade of old kits in new boxes.
The first which came into my mind, when reading you post Harry, is the Revell '56 Ford Pickup.