Its simply a cost thing as the majority of gros michel bannana plants in areas with the fungus will die every few years as infection takes that long, and most areas gained the fungus during the peak of gros miachel cultivation. But at a small scale you can avoid the fungus or just plant new plants when the fungus takes hold, its just more expensive and limited in scale.

Actually, possibly not. https://youtu.be/I9ZtvpBoXzI

It just has more isoamyl acetate, which is what artificial banana flavoring uses.

I keep on hearing this fact but I haven't tasted Gros Michel so I don't know. Fact or factoid who knows