For a second I’m going to try to think of what you are saying with an instrument that I’m not familiar with. I haven’t personally played flute, so how could a $1,500 flute and a $3,000 flute be that much different and would it justify a purchase? Regarding quality differences –even if you have experience playing the flute, violin or any instrument, it really doesn’t bring light to differences in musical upgrades until you experience them for yourself. I would go for the $1,500 flute before the $3,000 every time if I didn’t know truly how much it was going to help me.
I see your point about the never ending chase. It sounds horrible to be down that path you are saying if you have other obligations! There has to be a balance here where you feel that your dedication and spirit are enough to justify a higher purchase. Going from $1,500 to $3,000 is significant, and you would definitely want to feel you are dedicated and into playing enough to go ahead with an upgrade like that. But it wouldn’t make sense to do that if you did have high credit card bills and there are other things that have to be handled first. Obviously this sort of upgrade (even if it is justified) needs the player to have the funds to afford it. That is why payment plans are nice!
So how much more would a $3,000 violin improve your sound compared to a $1,500 violin? Lots more. But it would make sense to go through the process of try-before-you-buy with various shops to prove that increase in sound quality. That is my suggestion to those that are on the fence of upgrading to something nicer.