Microsoft makes shitty products that are not well designed or tested. Simple.
MS has made flops, but also products they've worked hard on and made good over time. All tech companies have shitty things happen in their product life. Even car manufacturers. First-gen Mitsubishi Outlander - not a great car. Avoid. 2nd gen Outlander and above (2006+), new engine, better design, better features... very good car.
Most other products, historically are crap. Microsoft always half-asses things and comes up with products that are irrelevant to the end user. Windows 8? I'd say it's a failure of epic proportions. Microsoft doesn't seem to care about the user experience - I always get a feeling that someone at Microsoft was thinking "Oh, we are getting stale, so we need to do something new - let's come up with this entirely new UI, but we're not really going to put any thought into how it is designed, and we are definitely not going to pay attention to detail".
In OS terms, Windows was always ages behind OS X and Linux IMO - but at least Windows 7 was "perfected", or as close to "perfected" as Microsoft can get. Ever since I switched to OS X, I have not used Windows willingly, and that's 3 years.
What it feels like you may instead be trying to say is "I don't like Windows 8 and think Linux/OS X are better", which is certainly a valid opinion statement. I wouldn't, however, labor under the misunderstanding that Microsoft doesn't care about users - hyperbole aside, do you actually think that of a company of about 100K people doesn't care about other people?
If you've ever worked on a big tech product, you know that agonizing amounts of attention are spent worrying about even the smallest details. Ultimately, that might mean that we don't always make the best possible decision, but I think it would be tough to say that Microsoft "half-assed" much.
It makes sense that you don't like the product; not everyone does. But it seems foolish to equate your dislike with a) it being objectively bad, b) it being half-assed, c) it being irrelevant (particularly when it plays a huge role in the world), or d) that the people creating it don't care about it or you. Indeed, d) is particularly important - isn't it grand that you live in a tech world where someone like me, who works at Microsoft, cares about your thoughts and feelings, even though you don't use Windows?
Microsoft (and many other companies) don't just care about the people who use our products...we also care about the people who don't.
The main reason for Microsoft's market share is a historical one: They partnered with IBM in the 80s, then PCs (IBM compatibles) became the de facto standard.
Add to this the abuse to the progression of the Web that is Internet Explorer. As many of the HN readers are web developers, well, do the math.