Would that be the same Cray 1 that in 1975 ran at over 10x the clockspeed of your first Amiga and supported SIMD/vector execution?
Yes, that one. Cost million of dollars, needed a room to operate, had a power consumption of 15000 Watts (or something similar), no ide hard disks, and probably some I didn't mention. That's not very modern.
An A1200 with a 50 Mhz '030 isn't quite as fast (it wouldn't be even at the same clock speed), but it's cheap, easy to operate, doesn't use much power, and if it's Ide, it'll run it (with drivers) and of course it doesn't need a room to operate and has a nice (although simple) multitasking GUI OS. No contest really.
This is exactly what I mean with computing in the 70ties and before VS the 80ties and after. The Cray 1 is probably still more powerful than the fastest 680x0 based Amiga, but I wouldn't want one even if you paid me, because they're not easy to use, while an Amiga is easy, just like peecees.
In terms of cars it would be simple: A horse and carriage is old fashioned, while high end sports cars from the 60ties aren't, they're simply outperformed by todays best sports cars. That's what I mean by modern.