One caveat here - Google devices are probably some of the most allowing of root access and full device ownership - easily unlocked bootloaders basically allow it to be a one button process.
Some manufacturers make you put your device on a shitlist with them before they'll give you a key to unlock the bootloader and root it - others, like Apple, won't allow you to at all.
Once you are rooted, you do have full ability to block everything and get fine-grained permission control via XPrivacy for example. Android devices are actually some of the best here mostly due to strong community support. You can't even get this control if you want it on many mobile devices these days.