If you look at what the Amiga was, idealistically speaking, at the time of the A1000's launch compared to IBM XT or AT PCs and apply that situation today you would need to produce a machine that was 5x more powerful but for the same price via clever custom hardware.
This is doubtful, although there is room for improvement because if you built a PC with the same raw CPU power as an Xbox 360 and identical graphics chip from ATI your PC's games would look nothing like as good as the DX10 games of a 360 but that's because it is running a bloated OS on a diverse open platform and the 360is not. You're not going to create a superior GPU in your garage compared to ATI/Nvidia and certainly not for less too so 'custom chips' as seen in the mid 80s are a difficult request as a technological price/performance solution.
Some of it IS down to OS and the fact you can't optimise PC games (running on win or linux) to the same level as a fixed hardware platform as a console like the 360, some down to just how sophisticated current hardware is.
So not really is the answer although if you wrote OS4 for the PS3 it would give high end PCs running any OS a good run for their money I suspect.
Early consoles at the time of the Amiga were quite sophisticated though too, Sega Genesis and NEC Turbo Grafix/PC Engine were quite adept at arcade ports, and usually superior to the Amiga port.
Look at it this way...you could produce a superior successor to a 60s Dodge Charger for less quite easily...but could you improve on a 2000s BMW M3 for less? Nope. The bar has been raised to high and the problem with PCs is not the hardware, simply the nature of the beast of an open diverse platform and the sorry state of a 'modern' OS written in some crap high level language taking up far too much RAM to replace the simple beauty of when Amiga Wb 1.2/1.3 was around in the Days of DOS/Windows or OS/2 etc.
