GLF5 driver nailed it.
During my aircraft acquisition days for the 'boss'...initially it was fun to explore new planes...now when I get the call from someone thinking about starting a flight department, I roll my eyes, especially when they say, 'I was thinking about a Hawker'..and have no idea what it costs, it's range, where it will be worked on etc.
I have known guys to drop out of school on one type, to start on another type because an aircraft buy fell through, and quite honestly no one really knew what they wanted.
In my opinion many of the purchased are driven by everything but raw performance...the boss likes the cabin, the pilot likes all the goodies in the cockpit, the pilot can't plan fuel, so he buys a plane with so much range, fuel planning won't be an issue...
Few times in my career have I been able to jump into a new plane, and that's usually due to the boss just wanting new...that's it...saving money had little to do with it.
These days I could probably speed up the process of purchasing a plane, getting the boss to a place where he knows what he wants by simply talking to him for an hour running through pictures in the controller.