And you ignore the time when Apple was nearly bankrupt, had less much less marketshare, a fraction of the yearly sales, and were much more obscure with mostly only ever seeing Macs in some dusty, dilapidated corner of a computer store (if lucky) yet had more viruses presents prior to Mac OS X.
When Mac OS X was out a couple years the argument was that it hasnt been on the market long enough, but its been over 8 years, or is that not enough time to write viruses for Mac OS X? Where is there 7% of the viruses? Where is the accountability for Macs costing double the average the non-Mac PC or that targeting cheap $400 machines to steal personal data would typically yield worse results than hacking a machine from a buyer willing to plop down a couple grand for a machine.
The argument is foolish that Macs are obscure. Even now we have viruses for phones. Its the nature of things. When your business mode is to create a platform any manufacturer can use and are required to support legacy code much longer than is necessary because of said business model it makes proactive safeguarding considerably more difficult, if not impossible. As a result Android is much more susceptible to more malicious attacks than WebOS, iOS, WP7 or BB OS. Its the nature of things. The more you spread your kingdom the less overall fortified it becomes.
Macs are becoming more prevalent, yes.
I work in a business that is run and operated on Macs. I have no beef with Apple or Macintosh. I think they are great machines! However, you are completely missing the point. Viruses have traditionally been very windows centric because that is, was, and continues to be the DOMINATE OPERATING SYSTEM! Just because the macintosh is exploding in sales right now doesnt mean that all the virus, malware, and spyware writers jump ship tomorrow and start writing everything for mac. It takes time. So what if mac users have more disposable income? If I wanted to create a phishing scam, I would rather target the largest audience because I have a MUCH greater chance of getting many more people to fork over money. A virus writer would rather take the 1000 people with 5 dollars to lose than 100 people with 10 dollars to lose.
For petes sake every Mac head in my company will tell you that the major advantage of being in the minority is not having to be the target of crapware. Sure, UNIX-esque operating systems are inherently more secure, but not completely impenetrable.
As a matter of fact, if you actually look around, Macintosh viruses are becoming a growing concern, because, as you say, macs ARE becoming more popular. Not to mention the fact, even though Macs cant be infected by windows viruses, they can be carriers and spread the infection onto someone who is running windows.
Have you heard about OSX.Trojan.iServices.A? It was a mac trojan distributed with pirated copies of iLife '09.
I wish only the best for Apple and their products. I plan to own one someday, but on the same token, dont be foolish by thinking that macs can never be infected by viruses. You will end up getting yourself, and most likely others infected.