Will next-gen consoles put our current gaming PCs to the test ?

Hello all, my brother is considering building his gaming PC, but he's convinced that the next generation of consoles (Xbox 720 and PS4) will change the whole game. He thinks that future games will rely on heavier engines, requiring a lot more horsepower than current PCs now have.

It was my understanding that the current consoles were way less powerful than today's average gaming PCs, and that the next gen consoles would still be underpowered compared to relatively high-end PCs (at around $1000).

I still think console games only look decent because developers have had time to optimize them over the years, but that a modern gaming PC will be able to handle the games which will come out for the next few years.

Am I wrong ? Thanks for your insight