IOS reading list doesn’t work offline

I find the Send to Instapaper button to be perfect for archiving because it's so ubiquitous. The glue that gets your articles from there to Evernote is IFTTT.

Just create a rule that says anything you save to Instapaper gets imported to Evernote and you're set. I believe you can automatically have it add a tag at the same time.

You have to remove an article from the reading list to purge the contents.

I suppose there is an implied storage limit since you would run out of space on a device once the cached pages exceed the local storage capacity and/or the capacity of iCloud to manage the content across devices.

I haven't tested it, but iOS has the ability to mark some content as cloud backed / temporary and these articles might get culled if you reach a low storage watermark on iOS, but I've never witnessed that happen even on devices where I've run quite full.