It could be worth a whole lot more than a mere $2000. If you feel good, you play good. If it looks good, you feel good. If you think that silver plated keys on a gold plated body is way cooler than a regular brass body, then that's all it takes for you to feel better. Consequently, you play better.
Of cause at some point the actual sound that comes out of the bell is important. The way the keys works, the action of it is important. But at $4000 it's all dam pretty good anyway. From there on it's more or less a matter of what brand you prefer. Which metal plating/ colours. Stuff like that. (Feel free to add a $1000 or two on mouthpieces too)