Amiga Ones, Sam440s and any future hardware machines are nothing but hardware dongles. They are there to prevent piracy, which would exist if one could just buy mac mini and put in a cd. More than half of folks here would no doubt do it. One has seen piracy on the classic amigas, it is no wonder that a great deal of software developers got pi**ed and left the amiga market (before commodore's demise).
You need Sam440 to keep people honest and buy it with the hardware, instead of just making a copy of the OS. (if you do not like that then get another Amiga alternative OS).
However, I do agree that sam440 is underpowered and something better should be available.
Prices - well, you want real support by real companies? Then yeah they will be higher than for Mac or PC as this Amiga Market is small and has always been dwindling.
