It seems we live in different worlds. In world I live and work, MS mindshare is doing well.
But that is actually irrelevant, because even if your statement is true for your environment, mindshare has nothing to do with relevancy.
Milk, bread, butter and water mindshares are pretty poor these days. People talk about milk only when price jumps. Same with petrol, electricity. That is because all of them are constant part of our everyday, and it is our nature to pay more attention to things less common in our everyday existence. I will talk with my wife and my friends about our next year trip to Barcelona for hours, plan what to do, what to see, yet I will not have a second thought about water - I will drink it when I am thirsty, and that is all. I am expecting water to be there for me when I need it, nothing more, nothing less.
But just because water doesn't occupy my mind these days, not even remotely much as travelling, or buying a new smartphone, camera or computer, does not mean water is irrelevant. It only means I'm taking it for granted. If water is to disappear from the face of earth, it will suddenly take a lot of mindshare, take my word for that.
Same with Microsoft. It is nowadays so common, everyday, heck a bit boring. We have to use it on daily basis at work, and so many people had jobs they need, not jobs they want, so for them it even symbolises lack of success in their career, definitely not something they want to spend too much time thinking about. We don't think about it, and majority don't even know how much Microsoft technology is built in whatever they do, whenever they do.
But all that has nothing to do about relevancy.
Re IBM server... no, it is not the same. IBM server can easily be replaced with Lenovo, HP or DELL server. If you are virtualising, you don't even need to think about hardware drivers and other potential difference. All that because IBM servers are compatible with Windows, like any other brand servers.
Today, there is no replacement for Microsoft. You can replace some products, but as a whole, no. That is the part I'm finding scary, so many things depending on one company. But that is reality, and that is relevance. Not mindshare. relevance.
I think I made my opinion reasonably clear, so I will stop here. If you managed to find a spot on this planet where Internet, credit card, cable TV, emergency services and everything else you need, like or just use work fine without Microsoft products, well good on you.
Only problem is... I don't think so.
I think we obviously have different ideas of relevance. You are focused on the past. I'm focused on the future. For the future of computing, as things stand at present, Microsoft will have little or no influence. I don't see anything going on in Redmond that will change that.