In Android at least, only one application can be running at the same time (no background processing unless you program a service for your app)
And the rest of what you say has nothing to do with Android or ChromeOS. You can have access to root in both. Android devices generally have it disabled but it can be enabled - of course, even CyanogenMod discourages root access these days, as it shouldn't be necessary. ChromeOS? Off by default, but every ChromeBook let's you reconfigure ChromeOS to allow root if you desperately want it. As for "Spyware", it's entirely up to you whether you use Google's services or not.
And none of your objections have anything to do with the original point. You're complaining about the UI disabling certain features. The underlying operating system has those features. And, frankly, easy access to root was something that Windows 95 gave you by default that NT made a little harder to get...