Archive.is is a different service, it’s indispensable but it saves the page for the future, outline.com is/was only making the article more readable by extracting only the text, and it doesn’t save anything offline, it’s also way more fast than archive.is. It is/was something like an Instapaper whiteout the login.
In effect tho, using reader mode in the browser on archive.[a-z]* is about the same as outline.
The problem is some brilliant product manager decided that the reader mode button should not be available on all websites and should only be available on those it seems to be articles.
I’ve never had reader mode not work on archive.is
Which browser do you use? I've never seen it work on archive.is in Firefox. Case in point: https://archive.is/ZPvrO
Specifically only speaking of iOS and Safari. Don’t have FF installed and have never found reader mode option in Chrome.