Steve Ballmer was an underrated CEO

He's underrated in the sense that a lot of CEOs of his era completely destroyed their companies, see Intel, GE, GM, Yahoo, etc and he didn't. So that's already a win, he set up the company in a decent position so that when someone with more vision takes over they'll have something to work with, even if he didn't have the talent to pull things off himself. He had a couple of wins (Azure, Office 365) along with many many losses, and they're good enough to secure him a 6/10 on my ratings.

If you trust the article, then Azure and O365 are each, independently, easily Fortune 100 companies if separated. These "couple of wins along with many many losses" are some of the most valuable products in the world.

Imagine a VC fund that invested in a few dozen product companies, two of which were Azure and O365. Is that a 6/10 VC company? Why is the logic different for a CEO making bets for a company's next several decades?

Because the company has more strategic resources than a VC, and has need to defend existing businesses.

MS should've been able to simply just extend their OS monopoly into all platforms and all architectures, but they didn't, and to a vast swath of the world have become irrelevant, and worse, have lost their ability to become relevant.

It's a decline from being the monopolist to simply a player, sure they executed well in enterprise sales and was fast in picking up OpenAI, but they have lost the ability to use their strategic resources to save xbox, help azure overcome competition, or push a mixer or Surface or whatever.

Edit: For people who don't understand the last sentence think about the way that O365 was able to help MS push Teams to stave off Zoom and others despite being objectively trash. MS should've been able to keep control of the internet, but they lost their moat to Google (Chrome), and the same story for various consumer products. Bing was a decent win but with a better consumer story they should've also been able to threaten social and youtube and so on. But now they're completely irrelevant there.