The company mission is just one of the Sillicon Valley tropes, another one is the idea of "changing the world".
Having a mission might be useful for focus and clarity in thinking but if it's taken as something more than that, it's just an artificial constraint. If you can use the company capital more effectively in a completely different market, you should do that, regardless the mission.
I feel that the mission is often constructed backwards from the products. I.e. at Google they looked at their products and came up with a broad description of the user need (organizing the world's information).
It's "Do No Evil," ethos/mission was important and having one & sticking to it is equally important vs. swiping it under the carpet for the sake of profits. Further it's mission was important to all the women and men they inspired to start up and to get into tech. Yet once they brushed their mission under the rug & focused on money many who they inspired became shocked to learn that many times they do 'Evil," prompting disenchantment. You can see that disenchantment with Google everyday here on Hacker News with the various negative stories and comments about Google. Something I bet if you go back more then five or six years you'd never see here.
Maybe you think of it this way because of how much its abused. At its core, I do sincerely believe (still) that Silicon Valley does represent a unique force of change in this world unlike any we've seen before.
Semiconductors and then Software: it has changed the world (for better or worse, that's another question).
All their 'random' stuff makes sense in that context.
Injecting Google intro the interface for brick and mortar businesses is why Maps and Android exist.
It would be nice to see a focused mission from El Goog. From the outside it feels like they incubate a bunch of random semi-competing products which are arbitrarily terminated or boosted. There's a lot of talent that could be marshaled.