In conversation with a friend today, he made a passing remark:
How can Google's own emails look like crap when viewed in Gmail, on a Google phone, using Google's dark mode?
I think there are three things at play here.
The first is that Google isn't just one thing. It's thousands of groups, mostly working independently. Of course we know this, but it's easy to forget when we use the shorthand of talking about a vast multinational corporation as a single thing.
The second thing is incentives. From the discussions I've seen online, it appears that Google's promotion and bonus program heavily weights launching new features and products. Diligent maintenance of a valuable but unglamorous part of their ecosystem such as Calendar or Hangouts is, they say, not the way to get ahead.
The third possible factor is that no one person is seen as responsible for the format of the email, so it's easy enough for no one to feel it's Their Job to make sure it's high quality. If you have a bunch of other things to do, and nobody will really notice or hold you responsible for cutting this corner, why bother? (One response to is that someone high in trait conscientiousness just wouldn't let it go, even if they thought nobody would care. But if the previous paragraph is correct, it seems like those people are probably slowly drummed out of Google by a structure that they would find irritating.)
So the problem my friend identified is that an email sent by YouTube, viewed on an Android phone running dark mode, in the Gmail app looks bad.
In the first place, it makes more sense to think of YouTube, Android, and Gmail as three separate companies that have a common owner and get to run their services on Google's Cloud (a fourth quasi-entity). After that, it comes down to whoever wrote the template to generate the email. Perhaps the template predates the widespread rollout of Dark Mode in the past two years, and nobody is eager to go back and audit every screen.
Broken down like that, it's really more a surprise that problems like this don't happen more often.