Yes, the guitar/singer format seems to be by far the most popular. I think people have seen/heard enough karaoke and probably assume a keyboardist is just working some sort of karaoke machine.

I got to visit some very luxurious hotels on the SO CA coast recently, and all of them had very good guitars/singers (no tracks) No Great American Song Book material. 60's to today's hits performed in an all acoustic format went over very well.

Here in the U.S (from my observations) for solo live music acts guitar/singer is by far the most popular, after that it's solo piano (sometimes with vocals but usually instrumental) Occasionally a solo singer singing to tracks on their lap top.
I almost never see anyone performing with an arranger keyboard, expect in Mexico, where it's pretty common.