At least there is an option if you want to. Compare to that to the Android's biggest rival, where different browsers are glorified skins on top of Webkit.
You're getting downvoted for trivializing the user confusion around replacing it, but when I first got Android I did want to get rid of it, and originally didn't know how.
So this is potentially useful information if you've gotten to this point in the thread and are suddenly saying, "wait, I can remove that?"
Are launchers fully replaceable now? I remember years back you could run another launcher but the default launcher process would still execute and remain in the background. Not really a 0 cost choice at that point - especially when phones had weak hardware.
It doesn't seem to be entirely isolated. Apparently going back to the old app switcher requires you to freeze or uninstall the system launcher, no matter what launcher you're using.
Gotcha, ok. I started using Android ~1.5 I believe, so things have changed radically since the beginning. I recall this being the case in ~2.2 perhaps.
I used Android from 2.0 to 4.4, and the phones I had performed notably better with third party launchers, suggesting the original launcher process wasn't still using system resources.