I bought a second hand mountain bike designed for riding single track around 2005 in the US for $600, what I wanted would have been $2000 and the best were $300

I bought a second hand mountain bike designed for riding single track around 2005 in the US for $600, what I wanted would have been $2000 and the best were $3000-4000 new. Today the high end is higher but the low end feels about the same, although technology has progressed and you get a more advanced bike for the money now.