That would be a very different context. You can't just take the same story and apply it to a different subset of companies. If Apple were to do this, it would be a very different situation since by doing so, they risk losing market share. Amazon won't lose anything from this, they can only gain.

Two of those four do, more or less, via the Coalition for Patent Fairness — http://www.patentfairness.org/learn/who/supporters/

(Disclaimer: my employer is also a member, and I approve, but play no part.)

likely not, because they are already in "the battle" and have been on both ends of the barrel, they're not on the outside looking in and considering that they'd prefer not eating a broadside.