90% it's engineers doing something they think is cool/kooky/funky without thinking about the consequences. As in, you know those top two sites have taken a hit on revenue because someone on a fat salary at Google wanted to do something cool with their 20% time, or some similar story.

But there's always this 10% suspicion, which is perhaps amplified by the controversy around AMP - and maybe it's a little bit unfair - that they ultimately never want you to leave the Google site.

That may be the case but, even if it's not, they do this stuff that they think is cool, but they do it without any sense of responsibility or empathy.

That solitaire game is a fairly limited implementation - admittedly rather a nice one - and it lacks a lot of the variants, and other bells and whistles of the top solitaire sites. Nevertheless it's going to be up there for all time, stealing traffic from and reducing the revenue to those other sites, and it won't make a jot of difference either way to Google.

I don't really think that's OK.