My point makes total sense. What part are you having troubles understanding?
Using your logic, Gibson should also discontinue Tobias, Slingerland drums, Valley Arts and Kramer guitars. Just because a company has multiple products that each have a very small market share, the sum of the whole CAN be significant.
Gibson basses are a very small part of Gibson's overall business. I don't think anyone can argue that.
Should they discontinue them and would that make good business sense? Not if they sell a couple/few thousand MIA instruments a year and are making a few hundred bucks in margin on each one.