people are also assuming that the partnership is completely dissolved. Panasonic could setup their own compatible battery factory. It would be good for the industry, Tesla and the alternative users. Just consider how popular 18650's have become in the last few years, they are in power tools, cars, phone chargers, radios and a bunch of other stuff.
Tesla never said they will ditch their battery suppliers. They explicitly said they will not be able to produce all of the batteries they need, since they will need astonishing amounts of them.