I agree with you but at the same time I don't agree with you. Times have changed, computers are NOT only for experienced users to use in secret labs, they are now our everyday appliances. Computers are so common now that it's weird when you run into someone without an email address.
I just hate it when people say, "IF YOU KNOW WHAT YOU ARE DOING" Windows can run just fine. If after all these years of advancement in computers that you still have to be an experienced user to maintain the Registry and that complicated Device Manager and all those retarded .DLL files then Microsoft needs to fix Windows.
The majority of todays computer users are NOT experienced computer users and they should not have to know how to do all the required maintenance on Windows and avoid all the nasties on the web because Internet Explorer will catch a worm.
Do you expect your parents or grandparents to do all of this? Would you spend the time teaching them all of this? Probably not.
A Macintosh runs the way a computer SHOULD run. It works for it's user.
The user does NOT need to maintain their registry and .dll files. Really, even the most advanced users don't touch these any more often than you manually edit .plist files in Mac OS X. As far as the device manager is concerned, it's really come down to being a pretty user-friendly tool for hardware management. It's just a list where you can remove or install drivers for a certain device in your machine...
Anyway, I wasn't talking about this kind of "knowing what you're doing". When I go fix my friends' Windows boxes, most of the time they have problems with malware, adware and similar bad stuff that slows their machines down. Unfortunately it takes a smart user to avoid this kind of software - this is the "know what you're doing" I meant.
There is very little of this kind of software on Macs, but the fact is it's because of their numbers (here in Europe, they're miniscule). I'm not trying to get into the "OS X isn't more secure, it's less popular" argument, it's true a Windows worm that requires no user interaction comes by every now and then, but these don't cause most of the problems. In my experience people install stuff they shouldn't by themselves 90% of the time. You download a piece of software and install it - whoops, it came with bundled adware. A friend gives you a link on MSN, you click it, download an executable and run it - you get malware. You download a COOL smiley pack for your IM client - it gives you a trojan.
There is absolutely no way this can be prevented by OS creators - you can't prevent the user from executing something if he wants to. UAC in Vista dims your screen and pops up a warning "This might be bad, you sure you want to run it?" - people still say YES.
So yeah, if you took 100 dumb users, gave half of them Macs and half PCs, the PC ones would end up with MUCH more problems and slowdowns after some time - not because of poor security, but because they are all PEBKAC cases. If OS X would be as dominating as Windows, I am convinced it would be the other way around.