Such as? Look at OS4, MorphOS and AROS, there you have plenty of hardware way faster than that of classic Amiga, way faster than AC 68080, yet... the software issue remains. Besides, the Vampire is not that much faster than a 060, especially since the 060 has a well supporter FPU. To really take advantage of the AC 68080, you need software written especially for it, you need dedicated support in toolchains and compilers - or do people expect developers to manually optimise all applications by hand using asm?
So it is almost comparable with a 5 year old smart phone 
Bit rough taking one component of a contextual holistic response and tearing it down. It stands in context with the other reasons. Your alternates don't.
