Wow, one of our solutions is nearly 100 projects (legacy) and the compile time for the whole solution is sub-5 minutes. I'd love to see what kind of solution would take 40 minutes to compile! (or maybe I don't :)).
That being said, C# is clever enough to only need to recompile the assemblies affected by your code change, so often you can get away with 10 second compile times even for large solutions.
IIRC our solution was around 450 projects. Visual Studio just woudn't open the whole solution.
So you had to work in individual projects at a time, slowly going through and changing stuff project by project.
VS wouldn't even build it either, really. YOu had to build via batch file that did various ms build magic. I would make changes, set of a build and go to lunch, then come back and fix the errors.
Once you checked the code into source control it would trigger a build which would sometimes take upwards of an hour :( I hated that code base.
It got even worse when they added Coded UI tests. Wait an hour for a build and then a random Coded UI test would fail and the advice from the people who wrote the Coded UI was "just run another build!", yeah, flakey tests on a code bases that tests an hour to run...
I've had a reviewer in a (scientific) journal tell me some paper is relevant, and thus I need to cite it, because it "appears on their top google results".
People should be educated on the huge bias introduced by personalized services like google.