Remember, there's a tipping point. When a high enough percentage of people start using a product, there's a tipping point where growth of that product will suddenly explode.
When only a few people use product X, then you won't know many people who use it, so it won't really be on your radar and it's easy for you to have an incorrect impression of it. And there is much less support for that product from 3rd party manufacturers. And humans have a herd mentality, things that you see a lot of other people using are subconsciously believed to be better, or at least safer.
So there's a tipping point - once enough people use product X, then all of a sudden all the barriers to buying product X suddenly start to fall at once. And once those barriers fall and more people start to buy product X, then the barriers quickly are eliminated further and further at a faster and faster rate.
Some people say the tipping point for non-MS OSes is 8% marketshare, some say 15% or higher, but all the analysts say that there is a
tipping point somewhere out there.
I agree with you at some level, but there are pluses and minuses to the situation.
Minuses:
Apple is a monopoly for Apple Hardware (obviously). For that very reason, they will only get limited penetration into the corporate world. Companies don't like spending big dollars moving into a specific hardware line and then have the rug pulled from under them. If Apple gets big enough and starts to license the specs to outside vendors (ie. Apple becomes more like MS) you'll see that position change.
Apple is expensive at first glance. Mom and Pop can get a PeeCee in Costco for $499 - complete. Looking at Mac Mini w/ no screen for the same price (assuming you can actually see one) isn't fair, but many look at the bottom line.
Pee Cee's are everywhere. Apple Stores aren't. That's changing with Best Buy and other big box stores starting to carry Apple brands, but they have a long way to go.
Pluses:
Word of Mouth. Let's face it, its cool to have a Mac. Some of it is Halo based from the consumer devices. Enough consumer penetration, and ultimately those people pressure companies to support the product.
Its not Microsoft. Let's face it, the whole verification lets crucify our customers, one license per machine, 400 versions but only 2 decent ones, your a thief nonsense is killing MS. I hear from so many people how fed up they are about this its unbelievable. And these are your normal home users. Even the OEM's hate the situation.
The world is Web Centric. You don't have to have a PC these days. Safari is more than good enough. There's some exception to this, but what do most consumers do? Surf the Web, shop the Web, Social Sites, Photos, Small Movies, pretty generic stuff.
Leopard - While its late, its reached Unix certification which is critical to government contracts. Those big fat $20,000 toilet type contracts! Also a plus for business, but not as critical for them.