it's all about the feel, the look, the prestige of a grand piano, which nothing else matches ...
JMHO
In the 70s when I worked for Avery Piano Providence in the sales department I once had a customer who came in purchased a high gloss off white 5 foot 1 baby grand. No one in the home played piano, he bought it for the look and prestiege. The guy never even flinched at the retail price. He did insist though that we give him a piece or 2 of sheet music so he could dsiplay it on the music rack of the piano.