Google is definitely more open in the way you describe, both in terms of collaborating internally and externally. "Googlers switch products often" matches my experience. The transfer process is easy, and hiring managers are welcoming.
The downside is that your team is constantly in flux, making it harder to build relationships or friendships. It is not healthy for a team to be constantly changing; it's better to have stable teams, where contributors can develop deep expertise and collaborative relationships.
At Apple, you have greater chances for meaningful ownership. Software teams are generally smaller, so your responsibilities are broader. Product direction is top down, so what you work on is more likely to actually ship.
Google's "bottom up" culture makes it easier to start up a project. But it also results in duplication, and a sense that the company isn't really committed to your product. My work at Apple mostly shipped, but my work at Google was mostly scrapped. It's frustrating to work on projects that are cancelled, through no fault of your own.
I wonder why we saw things differently? I stayed away from the big central codebase (you know the one), instead working in Android and Chrome. Maybe the bottom-up culture is more vibrant on the periphery?
AFAIK 20% time is dead, and has been for > the last 2 years. People only use it to try out new teams before transferring.
But I never did get access to the "other" codebase, so you know more than I in that respect. :)
I'm going to guess you're fairly junior in the profession?
The more time you spend writing code, the more you realize that most of your projects will never, ever ship. That's just how the gig goes.
And it's okay. As an engineer, you should be looking forward more to the journey and how much you'll learn working on that project than anything else. Once in a while, you'll ship and you'll feel pride knowing that millions of people are using your code, but that's the exception, not the rule.
Enjoy the journey.
Anyways, the way I see it, if I'm OK with my project being cancelled, I am working on the wrong project. We should not be comfortable with delivering results "once in a while."