It seems unlikely that Panasonic, LG Chem, Sony, Samsung, etc will cede all their current market share in EV battery production -- that is, 100% of the market -

It seems unlikely that Panasonic, LG Chem, Sony, Samsung, etc will cede all their current market share in EV battery production -- that is, 100% of the market -- to a company that currently has none whatsoever. Tesla doesn't make batteries right now... they make battery packs composed of batteries produced by Panasonic and LG Chem. The Gigafactory is basically space sharing: Panasonic's contracted to produce some billions of batteries there, while Tesla has space for assembly lines to package Panasonic's output into packs for cars and homes. Fast forward two years into the future: why would BMW definitely opt to buy Tesla packs of Panasonic batteries, instead of producing their own packs of Panasonic batteries, or Samsung batteries, or an integrated product from LG? LG has the US's largest battery factory in Michigan, which opened in 2013. They have production lines going for the Chevy Volt, Spark EV, Cadillac CT6, and several unnamed customers... and expect to grow production capacity at least 5x in the next 2-3 years. Like the Gigafactory, their output will be measured in gigawatt-hours per year. They also offer more than just batteries to EV makers. LG is providing the battery cells, battery packs, charging systems, motors, control software and infotainment system software for the Chevy Bolt for example. Tesla's unlikely to offer such a suite of components to other auto makers since they're competing in that space. That may make Tesla a less appealing potential partner, meaning they don't get revenue streams from everyone else's EVs as you imply.