To be fair, Rails is amazing, the most cutting-edge web framework out there, and it's settling into adulthood nicely. The Ruby ecosystem is so perfectly suited to web development that one hardly needs to go elsewhere to get what one needs. Whatever you could need is right at hand.
The .NET dev sitting across from me doesn't even use legit source control. He has his own hacked-together solution for his own projects, but most of what he does, he claims source control just doesn't work.
I think the main problem is that .NET tries to be all things to all devs, and so ends up solving no problems really well. People really seem to go gaga over C#, and to be sure the language isn't terrible like C/C++/Java, but it's pretty damn far from being spectacular. Ruby isn't the greatest thing since sliced bread either, but one can be enormously productive with it.