What I mean to say is, every product that is used by almost everybody will become a commodity at some point. That is not the question. The question is
a) How long can you keep it from not becoming a commodity?
b) How can you build your business model as market leader around it being a commodity?
E.g. gas stops can be considered a commodity at this point, but the powerhouse oil companies still own the whole thing and make hundreds of billions out of gas sales. If Tesla can use their leverage and tech-know-how to get into that position for electrical gas stations they might be in a good position to take that leadership position for a generation or two in providing electricity for the cars, making more money than with actual car sales.
So for Tesla, as much as for the not-yet-existing space station business, the fact that they will become commodities at some point is more of a strategic detail than a kill factor.