The RPi has a huge established market (Linux and/or geek users) and is really just a cheap embedded chip on a board with a few sockets - orders of magnitude less complex than an X1000.
They knew that because the unit cost was going to be SO low, they could produce millions and they would sell, and recoup costs.
Design costs of RPi: Much, much lower.
Market size of RPi: Much, much higher.
Risk of producing 1,000,000 Rpi and taking advantage of economies of scale: Much, much lower.
Making 1,000,000 RPi = make a fortune. Making 1,000,000 Amiga boards of similar spec to X1000 = suicide.
The two cannot be compared.