Well, i've never programmed a 68060 (only 68000 and 68040) but generally i would say the Amiga was/is a lot about assembly and hardware tricks. So if you can use it properly for a certain effect and come up with some clever code you can get out great results.
Honestly i'm not a Blitz3D expert but generally i think it looses through a) general commands which are never as optimized as special case calls and b) where it's not possible to do certain stuff this easily due to DirectX7 limitations.
A general purpose 3d engine will never be as fast like a special case scenario engine and the 68060 was a great cpu and you shouldn't just compared the clock rate.
Now if you add all these points together it should explain why you still can get out nice stuff on such old machines.
Honestly i'm not a Blitz3D expert but generally i think it looses through a) general commands which are never as optimized as special case calls and b) where it's not possible to do certain stuff this easily due to DirectX7 limitations.
A general purpose 3d engine will never be as fast like a special case scenario engine and the 68060 was a great cpu and you shouldn't just compared the clock rate.
Now if you add all these points together it should explain why you still can get out nice stuff on such old machines.