I'm not sure how you can argue that. Starfield does have some of mass effect's fun, but also I can build my own ship, dogfight a group of mercs in it, play house with the parts, disable and board a pirate ship in zero g... mass effect, in turn, has a much tighter story and gameplay loop. The core similarity is, what, that they have a space looter-shooter component?
They're different games. Starfield is kind of a fusion of mass effect and no man's sky, there are plenty of similarities between the three but also a lot of differences.
Was scrolling for this comment. I spent a few nights excitedly going over it with my friends before I learned about the internet meltdown, it was utterly baffling. I still can't really fathom it, it's one of the best SW movies ever made imo.