.NET is going no where, if anything it will get bigger over time
I hope your kidding, .NET is great for developing tools, remember MFC . Applications can greatly benefit from .net especially with portability.
If you were halfway decent at your job, you would have an imaging system setup so you would only have to install updates once.
You can slipstream .NET into any windows installer using free tools that are out there. If your just updating workstations, you could always update all workstations at once with a login script .
I've got to fix computers for friends and family the numerous .NET updates always make everything take AGES.
You could always stop volunteering to be so helpful , or you could teach them how to do it themselves.
I agree .net takes forever to install, but someone can correct me if i'm wrong, MS .net installers do a lot more than just install the .net runtimes, it also creates a system restore point which by itself takes ages.