This isn't a bad thing. Profit and price are, in most cases, still reasonable signals for what consumers want, and growing your market means you're serving real demand in the actual world. This is what creates employment and utility.

Flying to Mars and ignoring market share is nice but doesn't serve any actual point, other than Musks idiosyncratic desire for it. He can pursue it because in other areas the company actually does pay attention to growing their market and funding it.

But overall companies should pursue growing their market share because it means they're serving customers. I don't think the world would necessarily be better served if Walmart focussed on shooting rockets to the moon, rather than making it so the shelves are stocked and the products are cheap.