Well,
For one Why would anyone go Mono? We left that behind many decades ago....There is no PAN position, no stereo strings, no leslie effect, and many instruments will not sound good etc. And the 'Presence' is not there, and no seperation of instruments, drums etc. The reason stereo was invented was to give a feel of being in front of a live band, orchestra ect.

And, I will tell you that in many cases a better instument WILL make you a better player...Why? because when you have better sounds you are more inspired, practice more and then get better skills as you go...personal experience for over 40 years!

Does a better instrument INSTANTLY make your skills better...of course not.