> How can they be a "premium" brand if they already own a large percentage of the market?

That's what makes them one of the largest companies in the world.

Premium profit margins with commodity market share.

I'd say 17% of the computer market is sizable but still small and segmented enough to be premium. Macs don't factor into the purchasing decisions of the vast majority of ordinary people.

I’m trying to communicate they’d rather make more per unit sold, and lowering costs while maintaining quality increases is good for making more money. Maybe upscale would be better than premium.