There was an old adage that the best airliner would be designed by Lockheed, built by Boeing, and with Sales & Marketing by McDonnell Douglas.
Somewhere along the way Lockheed pulled out of commercial aircraft, while McDD pushed the profitability desire too far, didn't come up with much innovative, and priced it too high anyway, so production plummeted and they got absorbed by Boeing. Unfortunately some McDD executive attitudes came with the merger (those in the know may care to insert some individuals here) into the combined organisation, where from about the turn of the century it became the smart thing at the exec level to champion outsourcing everything while downplaying all those experienced in-house engineers who seemed so expensive. And thus they outsourced the future of the company to a whole string of lowest-bidders, with all that entails. Moving the exec offices from the city where they assemble their products to one 1,500 miles away didn't help.
We've already had the major fiasco of the fuselage production issues, which seriously delayed the production, and now the battery system which appears, somewhere along its own chain, unfit for purpose. Of course, if all that Boeing engineers' experience had not been got rid of, things might be a little different.
All this public talk of the battery manufacturer, the circuit manufacturer, and so on is not actually relevant to the purchasers of the aircraft, or indeed to others. This aircraft was built and sold by Boeing, they are the company that the airlines have the contractural arrangement with, they are responsible for integrating all their outsourcers, they are the ones responsible for the certification with the authorities, and they are the ones who receive the cash from their customers - or not, at the moment. One day I trust that Boeing will fully wake up to this.