It's not overly enterprise driven at all, from my perspective. The company I work for has teams totaling to about 40 or so developers and we're completely MSFT driven. From the DB side of SQL Server to web/backend of ASP.NET and .NET. And my understanding of the industry is we're hardly alone. In my area (the southeast US) there's plenty of opportunities at similar sized companies or smaller.
Achieving an intermediate skill set in any language/platform will certainly take more than a year. The language itself takes very little time - but picking up maintainable (Clean Code, Pragmattic Programmer, etc) habits takes a good bit longer for most people. Python probably has more beginner resources available thanks to MOOCs and the like, but there's plenty of .NET intro sources as well.
Achieving an intermediate skill set in any language/platform will certainly take more than a year. The language itself takes very little time - but picking up maintainable (Clean Code, Pragmattic Programmer, etc) habits takes a good bit longer for most people. Python probably has more beginner resources available thanks to MOOCs and the like, but there's plenty of .NET intro sources as well.