Surprisingly, it actually appears to be the other way around. (At least with regard to which group is naturally superior at operating a standard-layout sewing machine. I don’t know of any evidence that the disadvantaged righties are actually failing to “keep up the pace” and consequently “getting fired” from sewing-machine-operator jobs.)
Why does the standard sewing-machine design actually favor left-handers over right-handers in the modern world, contrary to what we might assume? Apparently because:
That second cite has an embedded video by a sewing machine manufacturer that is making a reverse-layout sewing machine to be easier for right-handers to operate, and watching it is blowing my (right-handed) mind. Yes, all the dexterity functions I have to perform with my sewing machine(s) are on the left side, and I do have to kind of cross my right hand over to the left side to achieve them, and it is a bit awkward and it would be more convenient to have all those functions on the right side instead!
All because so many early sewing machines were hand-crank-operated, and the manufacturers decided that the right-handed majority needed to be able to use the superior strength of their dominant hand more than its superior dexterity…