Why doesn't everyone use Windows?
Almost everyone does. Especially in business and government.
Why doesnt' everyone drive Fords?
Because cars wear out, and you are forced to switch to either a new Ford, or something else. Bitcoin doesn't wear out.
Why isn't everyone vegetarian?
Why doesn't everyone think that Britney Spears is the biggest superstar ever?
I have no idea why this is relevant
Like i said, I think Bitcoin's got failings that some of the others are trying to remedy... But I think a lot of people think that Bitcoin is perfect as is.
Sounds like a strawman argument, as I don't know anyone who does. Certainly not the developers who are continuing to fix problems and add issues. Certainly not businesses, who are still sitting on the sidelines, waiting for increased adoption and easier to use tools. And certainly not the users who find some things a hassle, and are hoarding coins with the expectation that eventually they will be easier to use, and thus will be worth more. If people thought it was perfect, everyone would be using it for transactions, and almost no one would hoard it, since there would be no future developments and adoption to "invest" in.
The point is that its a free market (god, I hate that word, sounds so libertarian!), and there's no reason why bitcoin should be the only choice. Just as we speak different languages, have different phone carriers, use different forms of paper money (sons people in fact freak out about the idea of a merged currency among the America's). People choose between debit and credit, paper or plastic, visa Amex Mastercard, choose among different banks and gas stations (whose final product is indistinguishable from that of their competitors). Contrary to your statement, there is in fact a contingent of people who use macs. There's also many people who use iOS and many more who opt for android, while others opt for blackberry. RHEL, Centos or Ubuntu? Postgres, MySQL, mariadb, oracle, SQL server or FileMaker?
So the point is, nowhere do you see a "this is good enough for everyone" approach, yet a lot of people think that bitcoin, with its 3 year history, ought to be it for peer to peer currencies. I digress - where some people see advantages, others will see flaws. The time to first confirmation is a huge one I think. The artificial cap on number of coins to be issued is another (I see zero advantage to this over a perpetually expanding monetary base). Those are big ones. Proof of work is resulting on a minor drain on resources, which is temporarily being fixed by ASICs, but once the arms race moves forward, I'm willing to bet that ASIC's will ultimately be the same power hogs as GPUs were....
More simply, and I say this as a complete hypocrite, having mined coins, sold them and bought from BFL while seeing dollar signs in my eyes, I think that the incentives in Bitcoin are completely upside down; people concentrate on mining as their road to riches rather than concieving businesses, and people hold coins close to their chest on hoping to simply profit from the fact that they hold those coins.... While I think mining (ie, issuing more currency and validatign transactions) needs to be a profitable activity for a peer to peer currency to take hold, think the reward structure needs to be rethought so that people are more focused on building an economy around a currency than to simply produce it and hope for demand to kick in.
So as you see, some of my complaints are based (I think) on what I think are shortcomings, other complaints are based more around the economy that's sprung up around Bitcoin in light of those shortcomings (ie the arms race to mine them since they're a limited resource and the hoarding effect that that has brought on).
Bitcoin is a pioneer, I'll give it that. The blockchain as the solution to the question of how a currency can be issued to tracked without a central authority is genius. So, there's no need to re-think that concept – other currencies can use Bitcoin as their “giant” whose shoulders they can stand on top of... Members of the community that think that Bitcoin is the be-all end-all solution can stick with Bitcoin, but remember, Satoshi released Bitcoin under an open-source license, fully understanding that not only would that mean that people could review his code and add to it under the “Bitcoin” umbrella and brand, but that other people might choose to take his work and go in a different direction with it.
I don't see why there are uproars when that happens, quite honestly. Worse are calls to actually attack the the competitors, and worse still are those who actually do attack currencies, simply because those currencies aren't Bitcoin.