- I'm not really sure Stadia can be called a "technical achievement at scale". Mainly because it didn't achieve all that much scale to begin with. Definitely a technical achievement in cloud gaming. But the implementation at scale is something that I now see Sony and Xbox working toward (along with their console partners - hardware and software).
- Youtube, definitely, given the content base, the number of active users at literally anytime, is a monumental achievement. But so are a bunch of porn websites. And I know the porn industry doesn't have a good rep. Even in engineering. Still, porn sees more active users than Youtube and netflix combined, albeit, on a bunch of different websites, but a few large enough websites that are comparable to Youtube in terms of active users, and catalogue size. Also, these companies manage to host all of this content and delivery it all over the world on a much smaller budget than Youtube. Not to take away any of Youtube's achievements, but from a technical point of view, I do think the porn industry wins. To begin with, porn streaming is older than youtube, but quite a few years actually. Additionally, from what I've heard, some of the popular live streams on OnlyFans (and similar websites) see more concurrent viewers than most YouTube live streams.