At first glance, Google becoming a car industry supplier like Delphi or Bosch seems just as weird. I kind of was expecting them to eventually go for the robocab business, with the steely bits manufactured by some Chinese OEM or underutilized plants in Detroit, Wolfsburg or wherever. It could be nicely phased in in limited access, limited range, low speed settings like e.g. island resorts.
But repeating the Android model, generously handing over software to whoever wants it so that they get a huge market share seems so much more consistent. This is Google, after all. If people can "ok Google" their car to actually take them to search results, Google's stranglehold on local business discovery will be even stronger than it is today. And on the reverse side, when it came to the point where people would "Hi Audi, take me to...", they could get quickly pushed of large parts of the search/decision market that originally emerged from web search and that they then so carefully extended to Maps, Android and voice assist. If cars become "Siri-smart", drivers won't use Google maps anymore. Seen like this, Google's self-driving endeavors suddenly appear like a forced defensive move, very much unlike the quirky billionaire's moonshot hobby vibe surrounding other parts of X.