Vettel is part of Red Bull folklore and has influence; winding up and crashing into a 4 time RB WDC was not a wise move; it ultimately cost Danill his drive.
If promotion, back to the works team came about, I don't doubt Danill will take in a heartbeat. Riccardo took the money, although, having been the top dog whilst beating Vettel - it was short lived when Verstappen arrived. The focus/politics of the team shifted - hung out to dry.
Danill has proven his resolve and if promoted to the factory works team, talk about gonads - make or break. A formidable obstacle, Verstappen is #1, Danill has to out perform and swing the team to back you...
Irrespective, if RBR have two strong compatible drivers - Ferrari and Mercedes will have a serious problem.
What an amazing narrative you've built there.
First off, Kvyat being demoted had absolutely nothing to do with Vettel. He was out before Russia, the decision was made, the paddock knew before Russia, it was his last race regardless. Verstappen had a clause in his contract that an offer from another team meant he could leave unless he was in the senior team. RBR couldn't lose Verstappen, I'm one of the bigger believes in Kvyat's ability but he's not Verstappen's level. Someone had to go and F1 isn't just about speed, it's about marketing, markets, appeal. Ricciardo beat out Kvyat in that sense in reality though I think Kvyat had the potential to be faster than Ricciardo long term. Russia isn't a big market for F1 despite the race and Ricciardo was much more popular around the world than Kvyat, who is funny but has a very dry Russian sense of humour and wasn't as widely liked.
As for Ricciardo being hung out to dry, nonsense. If this were Ferrari 1/2 situations then Ricciardo would have had his engine turned down so Max could get the youngest pole in Mexico, or sent out too late to do a lap, or forgotten his fuel, etc. They never once gave him a worse strategy(on purpose, at times they split strategy and it worked out better for Ricciardo than Max as many times as it favoured Max). Literally one thing he was ever asked to do or he could ever point to as a reason they favoured Max was asking him not to attack Max to the press after Baku, and every single team would ask every driver to do that regardless. Trashing your team mate in front of the press is just a bad thing for the team.
RBRs focus is on winning, nothing more, they haven't been in a title fight since Ricciardo was at RBR, the only thing they cared about was maximising podiums and getting the best result regardless of drivers. In a real title fight they'll favour whoever has a reasonable points lead and in reality it will be Max because he's considerably faster than Ricciardo, but if you get a Max crash/failure early season and Ricciardo in a tight fight with Hamilton and a real shot at the title they'd likely favour Ricciardo because they aren't stupid.
What you end up with though is correct, two strong drivers and Ferrari this year and potentially Merc in the next couple of years if Honda keep up their game will be real threat finally in this era of hybrid engines.
Though there are rumours that Merc are working on a 2020 engine that is the biggest change since 2014, which isn't surprising considering they've had a lead so had no real reason to risk it on a huge upgrade but since Ferrari are now ahead and Honda are almost caught up, they need to start upping their engine game again.