Let them do it MS
I'd like to see CERN go for it and after 3-5 years, as a in input to science of management and economy, calculate and publish transition costs, ongoing maintenance costs plus lost/gained productivity
Compared to EA terms.
Seen companies making the move from all-in MS and the only ones who succeeded did not do an ideological revolution but organically transferred services to various other vendors. Never cut completely from MS because it is just another vendor that provides solutions. Some of them are valuable enough not to replace them because of ideology.
Eventually everyone depends on someone else.
Of course CERN try to negotiate down the prices.
PR blackmail in negotiations is still a blackmail and it creates a very unhealthy relation.