I think the problem more than anything (from a Bruno point of view) is that he hasn't really enjoyed the luxury of being a part of a fully functioning team. Last season he only had Rashford and Casemiro (when he wasn't suspended) performing well around him. This season he's literally had no one bar Garnacho very occasionally. Mainoo and Højlund have stepped up recently and allowed Bruno to take more of a backseat role, but it's too little too late. Rashford is still a big problem and Casemiro has aged 10 years during his injury spell.
I see your point, but I consider him as one of the reasons for us being so dysfunctional (not simply because he is bad bla bla, but because the manager plays him (and the rest) the the way he does.)
Your argument can also be turned around because right now, Bruno might be one of the team mates which can be used for why Rashford is so off this season. So one badly performing player can give an alibi to the next badly performing player. As I said, I am not on the band wagon who wants to chase him out of the village but we have to play our cards right. Bruno is here for quite some time, he has been part of many dysfunctional teams and now we have to question ourselves, how far away are we from being one? And if it isn't really close, we should think about cashing in on him because as long as we have no functional team, he is what he is.
At the same time, I wouldn't be as optimistic as you are. As many have pointed out, even in a well oiled machine, there might be the chance of an upgrade. Brunos skillset is a little special because for the role he thrives in, he misses a few qualities like close control and dribbling that other players in those position have. Bruno might be better in different aspects than them but his standout qualities are his ability to quickly see and execute a pass. Add his injury record and fitness level and thats Bruno. Apart from that I don't consider him a standout anymore. He doesn't score enough anymore, his dead balls aren't great, his pressing attempts aren't well synchronized and for all the talk about his defensive shifts, I don't think he is really good there. He might be good for a 10ish player playing in the 10 area but for an 8, he is too weak. I think, in the last 8 weeks I've seen more and more players simply shrugging him off, outmuscling him.
So right now he seems like the lightweight 8 player with the great passes from time to time but because the rest of his skillset is not very complete, we are lacking in that areas of the pitch. Same applies to Eriksen. Same applies to McTominay (in terms of an incomplete skillset, obviously different strengths than Eriksen and Bruno). Add to that that Casemiro is losing his dynamism and Amrabat not really being up for it (it seems) and you have our midfield.
Keeping Bruno in the team means we have to adjust. The other two midfield players would have to be stronger types, defensively sound. That is why I thought the idea of Amrabat taking the Eriksen role from last season might be the way to go. Not as modern and forward thinking than I hoped but at least functional. ETH went for 2 high 8 instead, which is something, that doesn't seem to work with our players (at least with the injuries we had and have). We are a bit stuck in between the ideas it seems. And I think, we have to look forward and make sure to create the best team possible for in two years time. Bruno won't be in it so lets take the money, if somebody offers something.
Everyone else could honestly be sold as far as I'm concerned. But we need an actual squad (not to mention a starting eleven), so that's obviously not gonna happen.
I am also pretty triggerhappy so I can agree with your list. But we also have to keep in mind the list of the value of certain players. And Bruno sits relatively high on that list. Which, to me, tells me we have to cash in to get as much as possible.