BioSehnsucht
Model 3 LR
For the GF setup, does that matter? Tesla isn't buying cells from a separate external supplier, they are setting up supply chain to get raw materials to GF1 for Panasonic to use in Panasonic provided cell making machinery. If the machines work, where is the advantage in multiple suppliers? From a supplier point of view, all production is purchased so it would crazy to not work with Tesla (assuming a profitable sales price).
If the cells were externally sourced, then geographical or company diversification would be good to limit impact of a facility or corporate issue. With tooling in house, having two sections with two suppliers is no different than two sections with the same supplier (other than any supplier specific worker issues). If the contract allows Tesla takeover on Panasonic breach of deliveries, then Tesla is immune to most issues (other than the equipment getting repossessed? ).
The way GF is laid out, seems easy to simply say "This section is Panasonic, this section is Samsung, this ... ", with all getting an equal floor space. They could in theory try to leverage them against each other for better pricing for Tesla but that seems a risky and unnecessary move.
If they start expanding faster than any one cell manufacturer wants to invest though, perhaps then it makes sense. If Panasonic only is comfortable building out (making up numbers) 50GW/h a year, but they need to build out 100GW/h capacity, then perhaps lining up Samsung to take the other half makes sense. Even if Panasonic is 100% confident that the ROI is there, they may not have the cashflow / whatever to do so at some point, so hosting multiple suppliers can make sense simply from a scaling point of view.