You are probably referring to FxOS targeting emerging markets where smartphones were not common, so the hardware (thus cheaper) was expected to be very weak.

But really, hardware is not a problem from a marketing point of view, from a competition point of view. You can make FxOS to run on the best hardware with supported drivers, but the ecosystem is so behind, eventually users would move away from it. That was the real problem. Consequently, developers would likely give up on FxOS.

Samsung's are all based on Android - which tops iOS's market share by nearly 70%. Neither Ubuntu Touch nor FxOS had any real chances.