I have a feeling the group of people who side-load apps and the group of people who are willing to install a different OS are almost the same.

My wife is a case of someone who uses whatever comes on her phone. If I didn't mention it, she would not be aware that you can get apps other than via the Play store. It doesn't even enter her imagination.

So I'd say 99% of users won't even notice, because they weren't side loading in the first place.

devs

Direct install of apps going away on Android devices? Google approved apps only?

Signal312

I have a feeling the group of people who side-load apps and the group of people who are willing to install a different OS are almost the same. 

My wife is a case of someone who uses whatever comes on her phone. If I didn't mention it, she would not be aware that you can get apps other than via the Play store. It doesn't even enter her imagination. 

So I'd say 99% of users won't even notice, because they weren't side loading in the first place.