>> Many devs have bought into the iOS ecosystem. This certainly isn't cheap: macbooks, imacs, iphones, ipod touches, ipads.
It is a mobile tool chain. You don't need to use Macs for servers... (And the cost of an iPad, iPhone and iPod touch isn't high. You will need a phone anyway. And iPad is the only real game in town for pads, so you'll probably buy one anyway.)
The laptop I was already using for Rails development.
The notion that every dev getting into the iOS space was converting from Windows at an enormous upfront cost seems rather daft. OS X had a lot of dev traction before iOS existed.
I obviously don't have hard numbers on this but I can say from my own experience we purchased macs exclusively to build iOS apps for clients. We run a pretty lean shop so we viewed buying macs just for web dev a luxury item. We spent the money early-on on bigger monitors and beefy PCs for less than getting some MB Pros. However with iOS apps being something clients now want, we had to spend the money and of course buy the devices to test. The money spent upfront certainly wasn't trivial. But I admit we could be the anomaly; maybe we were the last shop on earth still coding on PCs. :)
It is a mobile tool chain. You don't need to use Macs for servers... (And the cost of an iPad, iPhone and iPod touch isn't high. You will need a phone anyway. And iPad is the only real game in town for pads, so you'll probably buy one anyway.)