It is true that the OS itself and many of the applications runs happily on Efika and Sam and other low power hardware. This is why MorphOS would have fitted so nicely in the LimePC devices. But then there are other applications that can't get enough of CPU power. Heavy multimedia stuff (like advanced flash animations, compression intensive video codecs, etc), rendering stuff, compiling stuff, etc. Try compiling a complete Linux distro from scratch on a Sam. Then do the same on a Pegasos2 G4, and then on a Mac Mini 1.5GHz. The Sam is too limited in power to be a desktop computer. The Efika was never really intended as one (but a development/evaluation platform for future e300 mobileGT CPU's) and gets away with it because of the low price. But if you pay the price of a workstation you could at least demand to get decent muscle power.

This "the Amiga has never been about high power CPU's" is just as stupid as "the Amiga has never been a cheap hobby".