Gabe15

The main reason is because it is such a popular plant that it is easily available as tissue cultured plants. It is not so easy to produce seeds of it in the US, as it would have to be grown in the right climate and managed just for seeds, which is a lot of work for a rather low value product. Other species such as M. velutina are easy to grow seed and very prolific, still yet other species are collected from the wild. I suppose also there is no one in the banana seed collecting business in the native ranges of M. basjoo.

If you grow one, most often they actually do not have seeds the fruit, and the fruit never develops at all. This is rather normal for wild species in cultivation as they just don't get pollinated, but also there may be an issue with the common M. basjoo clone being a sterile plant as well.

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Growing bananas in Colorado, Washington, Hawaii since 2004. Commercial banana farmer, 200+ varieties.