Well, that's the way it turned out. Nobody knew for sure that .com would have a stranglehold. Just like Coca Cola. I could give you 50 Billion dollars and you couldn't put a dent into Coca Cola sales. You may think you have a cola that tastes just as good, and after all, it is a cola, but there is one Coca Cola, and it is stronger than even Pepsi, though most adults prefer Pepsi. When people are at a restaurant and they ask for a coke, the waiter will often say: "is Pepsi ok?" They never ask for a Pepsi with the waiter then asking if Coke is ok. That is how strong Coca Cola is, and dotcom is even stronger than that, and the other extentions aren't even in Pepsi's league.
If someone told you about a website that was at .net, there is a good chance you would type in .com just out of habit, but if someone told you there was a website at .com, you would NEVER type in .net by accident. That is strong stuff, so why fight it? That is why it is a such a joke that those who pump the loser extentions actually think that if they sit around in their underwear and throw up a site at dotmobi or .us, or .co, that it actually matters. It is over before it even starts. Most all of the UDRP's are for dotcom names. That should also tell you something. Big companies mostly don't even care if you infringe on their names in loser extentions. Everyone knows that dotcom matters the most, by far.
Most of the alternate extentions fall into the obscure soda or pop league. It doesn't really matter that you can throw up a website on it. It cannot ever compete with coke, even if you gave away the drink for a nickel you can't overcome coke in sales. That is mind share (and usage) that you cannot overcome. People who drink 5 cokes today will be drinking 5 tomorrow, and all 5 will taste just as good....they won't get tired of it, either. They are not switching up to a cheaper brand. When it comes to making money you need to be in dotcom., unless you live in the United Kingdom you could use .co.uk. There are a few other extensions that are ok for specific country uses.
Dotcom is used everywhere....just like Cocal Cola. If Warren Buffett were a domain investor he would have only dotcom. He happens to own 10 percent of Coca Cola, as well.