First of all, Welcome to the forum Lee. I'm really enjoying reading your well-thought-out posts and insight. While I can believe that some of the things you are suggesting could be happening, I think the main thing was that Lewis was bored sitting at home (or where ever he was) and wanted to get back into the car. Of course he wouldn't be happy with someone else doing well in his car, so that only makes his feelings more urgent. Although George did great, Mercedes still has to keep their #1 star happy. George is shining right now, but it's still too early to know if he will ever be at Lewis's level consistently. Lewis has shown he can handle the pressure and deliver day in and day out, with George those kinds of things are still unknown.
The one point I'd have to disagree with you on is when you say Mercedes threw George under the bus. They gave him a great opportunity (at the expense of their own reserve driver) but I doubt it came with guarantees of the next weeks drive if he exceeded expectations. I think that opportunity was a good will offering towards the future. Right now, having Lewis behind is pretty much money in the bank. Why would Mercedes take the chance of cracking him mentally, or bruising his ego by telling him to sit out if he's cleared to go and wants to race?