It's not necessarily more expensive. The maturity of high end audio plus the rise of Chinese-sourced new components change the high end price/performance ratio.
12-07-11: Orpheus10
"Hi end" audio is all about diminishing returns. All separate and mono blocks yield the ultimate audio when this is what your ears require, and you listen to music enough to justify the expense.
Consider: My combination of Jolida phono and line stage pre's plus vintage tuner and 180wpc power amp cost me a total of $1007. You will *not* find a new receiver or integrated amp at that price that can touch the power, clarity, and musicality of this stack.
Even going new, you can get an Emotiva USP-1 pre (with phono stage) plus 125 wpc UPA-1 power amp for $658. You'd be hard-pressed to find a new integrated--let alone a receiver--that could approach its performance at that price. Entry-level separates are no longer the big jump in price compared to integrateds and receivers worth listening to. The only disadvantages are rack space requirements and the cost of interconnects.