One major reason the Farfisa didn't catch on was marketing. When it was first introduced, I saw an ad for it in a music magazine. I thought "wow, this thing has many more features than anything else on the market." I phoned the number in the ad. It was the U.S. distributor. I asked where I could see one. They couldn't tell me. The only place they knew that had one was in New York (if I remember correctly).
They offered to sell me one at full retail, sight unseen, with no return privilige.
I passed. This was before there were so many resources on the internet for such items.
I never saw another ad, never saw a dealer that handled them, and never saw it mentioned again until years later when Uncle Dave mentioned that he had one.
At the time it was introduced it was miles ahead of anything else on the market.
But I figured that with zero dealer support, and a brand new, unknown product, it wasn't worth taking a chance. What if it needed service?
Anyway, maybe that helps explain the lack of popularity.
DonM

"They offered to sell me one at full retail, sight unseen, with no return privilige."

WOW!!!!!!!!!