FWIW, I remember people saying this in 1999 as well...
There's also the "culture wars" to consider, where many (myself included) revered IBM for superior alternatives (OS/2), while old timers would just shake their head at anyone trusting them. Now, I shake my head at anyone trusting Microsoft, although they've tamped down their rabid attacks on open source and Linux, and they do offer some things that aren't complete garbage.
Incidentally, Microsoft co-developed OS/2 and there were only three problems with it: (1) you couldn't sell PCs running OS/2 -- IBM tried; (2) you couldn't get software houses to write programs for OS/2 -- except maybe Lotus; and (3) you couldn't get end users to install it. You had to install a whole OS to run OS/2, but Windows installed just like any other DOS program, and you could delete it if you decided you didn't like it.
Thanks to hiring Dave Cutler and staff from DEC, Microsoft could see a way out. However, IBM rejected the plan to move to NT as OS/2 3.0, and the two companies formally divorced. After that, IBM did its best to kill Microsoft. (One IBM senior manager told me: "We're going to burn Bill's butt.")
Bear in mind that in 1990, when Windows 3 came out, IBM had an annual turnover of $69 billion and Microsoft's turnover was $0.8 billion. It was a giant monopolist against a tiny start-up.
So, given the context, what was underhand about Microsoft's behavior, and what should it have done?
How did IBM's 1991 development of Workplace OS for PowerPC -- intended to cut both Microsoft and Intel out of the PC market -- fit into the strategy?
Microsoft's turnover had grown to $5.3 billion in 1995, but IBM's turnover was $72 billion, and it was still a brutal monopolist targeting a much smaller company.
I started programming in 1978, on IBM systems, and they were indeed "a brutal monopolist", probably feared more than Microsoft has ever been.
Sure, during the early-mid '90s Microsoft had sharp elbows and was looking out for its own interests, but those also just happened to coincide with ours. IBM was big, stupid and much more dangerous, UNIX(TM) was horribly fragmented (one of the core competencies I developed in the early '80s was porting software between different versions of it, and see The Unix Haters Handbook publishing in 1994: https://en.wikipedia.org/wiki/The_Unix-Haters_Handbook (disclaimer, Simson is a friend)).
GNU/the FSF was doing worthwhile stuff, but was and still is hanging fire on a kernel, the BSD porting efforts had been crippled by the '92-3 AT&T lawsuit, Linux was started from scratch in 1991 and immature, while NT was developed by well funded top notch experienced people (at least back then it was very rare if not unheard of for someone to develop more than one operating system, the process was so onerous) and was a great hope for a lot of us. In the mid '90s I developed or took part in developing several very solid systems using it, and I believe it's TCO and maintainability exceeded UNIX(TM) during that period.
Unfortunately, Microsoft started fumbling the ball about 3-4 years after NT's release (on or after the first Service Pack of NT 3.5 or more likely 3.51 as I recall), NT 4 was conceptually hopeless by moving graphics into the kernel, "and the rest is history".
Microsoft, of course, had a major problem, which was how to get the market to move from DOS-based Windows to NT. Not even offering OEMs 75% off the price of NT managed to shift them. Ultimately, Microsoft had to do whatever it took, and not all of it was nice. It didn't manage to do it until XP in 2001.
Re Unix, you have missed out the COSE/Hamilton group development of OSF/1, first released in 1991. This was supposed to unify most of the major players -- DEC, HP, IBM etc -- except Sun* behind a single Unix to prevent Microsoft from getting into corporate computing with NT.
Presumably you would have come across it....
* OSF = "Oppose Sun Forever" according to Scott McNealy
Yes, indeed, I used it in 1996-7 on the Alpha, just after it was renamed Digital Unix from DEC OSF/1 AXP. It was very nice, ran everything we wanted well, plus had a great High Availability capability. But I didn't view it as a major contender, back then at least, Sun provided the systems of choice. Assuming you could manage to buy them.
As for Win 16 -> Win 98 -> XP ... I don't know, I went from Windows 3.1 to NT, and as far as I could tell NT was better and more stable than the legacy non-memory protected stuff; hmmm, but I'll bet not for games (and NT4 putting graphics in the kernel was ugly). XP was great, and due to things mentioned elsewhere, I and then my parents used it for more than a decade.
I dual-booted the two types of Windows way back then, and it was just too hard to stay on the NT side....
To some extent (possibly a large extent), OSF/1 was a push against the AT&T/Sun effort to unify Unix with SVR4. It just ended up more fractured than ever, which was a shame.
There was a brief window when Unix could perhaps have been more successful. That was between DOS and the Windows vs OS/2 war, when Microsoft Xenix was relatively successful. However, IBM was dead against Unix at the time, and OS/2 EE was meant to be the IBM-owned cornerstone of its Systems Application Architecture.
Unix could run on everything from PCs to Amdahl mainframes and supercomputers, whereas IBM had two major mainframe operating systems, at least five on minicomputers, plus workstations and desktops. No wonder IBM saw Unix as a massive threat to its account control.
Otherwise, IBM claimed Workplace OS was new code.
NT, of course, wasn't written for x86 in the first place. It was intended to be cross-platform. It was also sold on PCs with DEC Alpha chips.
Otherwise, which tactics were unacceptable in the context of a small company being attacked by a giant monopolist that wanted to drive it out of business?
Microsoft realized that you couldn't force people to buy something they (rightly or wrongly) didn't want, and decided to sell them something they did want. Small companies are like that. Being a global giant with a long history of monopoly power (going back to the 1930s), IBM didn't think like that.
There are companies out there still shambling along that used to be dominant but are now ghostly memories of their former selves.
There's also, XBox itself and Azure, which are key points to the future of MS along with Office, which will now grow to other platforms, as it should have some time ago.
I thought Facebook was going to die out too then they became defacto telecoms in the developing world through WhatsApp/Internet.Org, and now have a billion users.