System76 aren't there. They sell rebranded ugly generic laptops with low quality screens. They sell them for a similar prices to low end macbooks. You put the average person in front of both in a store and they are going for the macbook. Better screen, better battery life and good quality hardware.
PopOS has the best chance to be 'the Linux' desktop. But they need nicer hardware. System76 are selling laptops to Linux people, that's their market. They don't have nice hardware design to compete in the high end of the market. And they aren't cheap enough to compete in the low end.
System76 are also going after the server market. I suspect they will go the way of Ubuntu. Chasing the server market and being too distracted to follow through with their desktop ambitions.