Don’t wish to sound like a socialist with a chip on my shoulder, but couldn’t agree more with binners!
Evolution will push the price of bikes up to a point, as will increasing costs of raw materials, shipping etc. But the biggest factor determining RRP’s of bikes, bearing in mind that this is a hobby/passtime not something that is necessary to live with, is simply “how much someone is willing to pay for it”. An as binners says, get yourself up to Llandegla on a weekend, and clearly you’ll see lots of people who are very cash rich, and probably quite time poor, who are prepared to spend several times what you or I would decree is a “decent” amount for a bike.
You can still get an exceptionally good MTB these days for less than £1k if you’re savvy and not a brand snob, and certainly £2k can buy you more than you’d ever need unless you’re on the cutting edge of competition.