Like what my MEP teacher told me about 20 years ago - music is an expensive hobby. If you want to excel in it, there's no way it's going to be cheap.
I don't really know where this thread is heading. Anyway, when I learned the piano at 4, my parents weren't rich. We stay in a rented apartment. But still, they got a Kawai for me. Of course I can't afford the expensive piano - but at least I get to play the grand every week in my piano teacher's place.
I don't think the issue is rich or poor. The issue isn't about more skills involved in piano playing. All musical instruments require skills. Somebody mention the violin as difficult - well, it has 4 strings and a guitar has 6. The only different is the bow and the fingers - which I don't think makes playing the violin more difficult than the guitar. Same with the piano - guitar uses 2 hands and most of the 10 fingers - so does the piano.
I think eventually (and sadly), it all comes to image and market. You see and hear guitars everywhere in rock/pop or whatever music you have. If all the music scenes involves only keyboards and pianos, I'm pretty sure people will take up the keyboard/piano on their own without any problems. All musical instruments are the same - need determination, patience and practice. If everybody plays the keyboard, I'm pretty sure the price will also go down making it more affordable.
Of course, wind instruments are slightly different since it also depends whether the person's lips had the particular embouchre for a particular instrument.