Obvious things that I don’t understand why noone has implemented

Here's my take on a couple of them:

1. Syncing of Cookies

This sounds like it could be a security nightmare. Cookies contain login information for sites and allowing another device to sync these could open you up to a compromised login.

2. Sematic Search

If I need to qualify "apple" as a fruit (instead of a company), then I can just google for "apple fruit". DuckDuckGo adds suggestions on their SERP but I honestly don't find it that useful.

3. Simple file-sharing

I agree on this one. Sharing large files is a nightmare.

4. Decent Text editor

Text editors are such a personal taste. Some people want Eclipse while others want VIM. I think OS makers are better off having third party vendors handle this.