Personal computers were like this for a number of years. From about the mid '80s to the early '90s, a solid mid-to-high level PC was $3000. Obviously they got faster and had more memory and storage, but the price didn't change much. Eventually volume got to the point that commoditization (is that a word??
) took over and the price dropped.
My prediction is that the pixel race will top out around 45mp, and in 10 years a FF prosumer camera will be $1500. The interesting question to me is whether that "standard" platform will be SLR or mirrorless.