I don't think that bass marketing policies are the source of Gibson's troubles. They have always tried to sustain models that sold reasonably and were not just niche: in the 60ies the EB/SG as the work horse (TBirds just didn't sell back then), in the 70ies the Ripper/Grabber/G-3 family, in the first half of the 80ies the Victory/Q-80/Q-90 line, after Henry took over they reintroduced the TBird in 87/88 (and kept producing it to this day), much of the 90ies were dominated by the LPB-1, -2 and -3, come the noughties and beyond, they introduced a wealth of basses, but only the SG Bass as the second coming of the EB-0/-3 proved a durable success (and that did stay in the catalogue together with the TBird). Other models have come and gone, but having established two iconic bass guitars (and as radically different as a TBird and an SG Bass to boot - you know how most non-bassists can't really tell a Jazz from a P!) - ain't bad. And both reintroduced during Henry J.'s tenure.