I've jailbroken my iOS devices since the first iPod touch. There are lots of tools and features that Apple doesn't allow developers access to which limits what features are ultimately available to the end-user.
Nearly every big feature release on iOS came first from the jailbreak community. App switching, call overlay, PIP video, Shortcuts, lockscreen widgets, home screen widgets... and an endless list of others.
Non of these features would exist without designers and developers having access to the core functionality of the iPhone.
I love iOS. I currently own an iPhone without a Jailbreak (doesn't exist for my iPhone). I'm also an engineer and there is a whole lot of potential that Apple limits strictly under the guise of security. You can have alternate stores without compromising those that choose not to install them.
I understand that Google may decide to create their own store and take all their apps with them... this I can see being a very negative thing which may be needs regulation in itself. IDK what that would look like, but I don't use Google anyways because I have no trust in them. I don't trust them in the App Store so I wouldn't trust them with their own store.