I wouldnt care too much about the logo. It’s a basic shape. You cannot pick a triangle for your logo and expect nobody else will use a variation of that.
There are plenty of logos that look just like React logo because of the generic shape of an atom. Eg: world nuclear university, physics departments in universities, etc.
It's obvious there would be a drop between xmas and new year. The problem here is that you're comparing AngularJS to React the latter of which is too broad of a term. You could narrow down the results by selecting "Programming" as a category:
https://www.google.com/trends/explore?cat=31&q=%2Fm%2F012l1vxv,AngularJS
I've tried fullscreen web apps before and it didn't work for me. A simple use case to illustrate where it failed in terms of UX:
- User clicks the "Forgot password" button and gets a password reset link to his mailbox. Clicks the link and hey, the reset password page is now opened in a new tab in Safari. Fullscreen experience ruined.
This also applies to things like logging in with your Facebook/Google/etc account, purchasing things (think Stripe).
Note: I'm talking iPhone here, unsure about Android devices