Addressing just a small point from this: a lot of people working on the web at the moment have absolutely zero interest in using Visual Studio. Like, say, all the people using Macs.
Visual Studio may be coming to OSX soon. MS recently announced .NET for Mac and made VS Community freely available; it's quite likely that they're planning to release VS for OSX/Linux soon too. There's also Omnisharp, which brings C# tooling to Sublime, Vim, Emacs et al.
I'd say there is plenty of interest in a cross-platform Visual Studio. It's hands down the best IDE I've ever used, and if it was available on OSX you can bet I'd use it. That said, since VS is not in fact cross-platform, some VS-specific feature obviously doesn't apply to those developers who don't run Windows.
Personally, I do C# development in a Windows VM, everything else in OSX. With the new vNext stuff, the only thing still binding me to Windows for anything is the lack of Visual Studio (and WPF). I wouldn't be surprised to see an effort made to bring it to a larger audience now that .NET is going cross-platform.
I was less commenting on PC vs MAC and more that Visual Studio is not used by web developers who use Sublime and WebStorm and other text editors. I believe you'll see VS move closer to those usage scenarios over time and have less of the stigma of being an MS-only tool. Or at least it _has to_ to survive. I'm a VS guy from the beginning, but I really like WebStorm.
Macs are hugely popular in Italy among web developers. What I usually see is in offices, coworking spaces and conferences is a sea of glowing apples, my Linux laptop (I don't like the OSX GUI), very few Windows laptops, usually not the ones of developers. After all if you deploy on Linux, why develop on Windows? OSX is a good enough approximation.
I don't know what the average salary is (I bet it's not very high) but paying € 1500-2000 every two to three years for a tool you use to work is not out of question. My HP laptop is in that range but it will probably last more than the typical MBP (crossing fingers). However people resell their Macs quite easily when it's time to buy a new one.
Furthermore the computer is a cost so it lowers the taxable income. According to our fiscal laws if you lease something (somebody does that with computers) then it is completely a cost. If you buy it, you can deduce only 20% per year over 5 years. This doesn't apply to goods sold for less than € 500.
Small companies are starting to buy Macs as well. Probably the boss can't have the face to keep a Mac for him/herself and give Windows boxes to the developers :-)
Large companies tend to stick to Windows PCs but they are becoming less inflexible. Again, people used to iPhones started to think that they could work with Macs as well and so it's starting from the top there too.
Just another data point: here in Betahaus in Barcelona, I would say that 80% of people are using macs.
I think it's less about salary (except to some degree of course) and more about culture. When I do consulting for corporations I also only see Microsoft and HP or IBM, whereas even somewhat struggling freelance graphics designers or developers will have macs.
