It is extremely hard to predict 15 years from now but the next five years?
There are no competitors(perhaps besides Chinese battery makers) everyone is still in early R&D\prototype phases.
Looks like some of this has been studied by Harvard Business School: https://www.hbs.edu/faculty/Pages/item.aspx?num=45289
Anyhow, you tout Tesla's deep work in batteries, motors and electronics (and let's not forget glass, doors, seats and other areas where Tesla has decided not to out-source). I can see where another company might be the GM to Tesla's Ford - finding success buying some of the right bits and pieces rather than spending an insane amount of money (re-)inventing them for themselves.
We need to advance the technology which is still not good enough for our global needs, but knowing where these two are.... I'm skeptical
Not all automakers have done things that way though, and other automakers are able to complete with Ford. Vertical integration can sometimes be an asset, other times the "Not Invented Here" culture proves limiting. Tesla's had incredible success thus far, but we probably need a couple more decades to see if they maintain their first mover advantage or if other players end up being more agile and more successful.
0: https://www.caranddriver.com/news/a23478147/ford-river-rouge...