I agree. My opinion is that once you've trained yourself to use virtual desktops efficiently, multiple monitors becomes more of a hassle than a benefit.

I think multiple monitors is the solution for people who would rather solve the problem by spending their money instead of the effort it takes to configure and become accustomed to switching between virtual desktops. Given that it is a strict biological limitation that the human brain can only focus attention on one thing at a time, I don't believe there is any valid argument for why moving your eyeballs between physical monitors is any better than hitting a key combo to switch between virtual desktops on a single monitor once those key combos have become muscle memory. Additionally, the number of physical monitors you have is limited by how much money you have to burn and how much physical space you have to place them, whereas virtual desktops are theoretically unlimited.