Yout have to factor in the life sim-element of Bethesda RPGs too. You can theoretically become a mining magnate in Starfield using those planets and resource extraction outposts. That content is there for those kind of players. If you just want to do the directed side content, then as you say, you'd just follow the markets and not need to interact with it. Your exploration will be in the "dungeons" looking about for lore and loot.