You gotta practice and you gotta invest into quality equipment, and continue to practice.
You can buy relatively cheap stuff and sit and complain as to why you're not getting the results you want.
Every thing else has been said from the emotional to the technical concepts.
You just have to grind it out and continue to progress in quality (skills and equipment).
I'd bury my head deep into skills though if i had to choose one. The equipment you choose helps refine skills in ways.
I totally agree with you on the importance of practice, but I can't say I feel the same about needing to invest in quality equipment. There are plenty of great musicians and producers that are successful with a minimalist approach to gear. Plenty of relatively inexpensive instruments and setups that can sound phenomenal in the right musician's hands and imo its not as much what you have as it is what you can do with it. The same principal can apply to production, great sounding records and songs have been made on equipment that would make your average audiophile cringe
You're right when it comes to music, but when you need to make decisions that will effect the overall sound of the song, then equipment matters.
The different between steel strings and flat wound strings on a bass, what type of bass, what type of cab and amp do effect the sound and the mood of the song.
Also, if you spend a minimum amount of money towards speakers, you won't get the same results as some one who has literally built a space dedicated towards the art of mixing. So, I will still defend my statement towards investing in quality gear. You shouldn't chase the high of equipment, but you'll need some standard equipment if you expect to take this further into a career.
Understanding your equipment and room limitations is the start of using your ears.
I mean, why do they even make such expensive equipment if you can't expect better quality?
But, you have to decide what you want for yourself.
Suggesting to some one that "oh you shouldn't aim for high aspirations" is selling yourself short and the person you're talking to.
Being realistic and asking about how far you/they want to go down the rabbit hole is what should be talked about more.
I am also talking about the MINIMUM towards a studio set up, not having all this outbound gear and what not. You need at least a specific prince range and size of speakers to hear what's going on. Same goes for mixing headphones.
So, I understand the importance of the choice in gear and the current level of producer/musician, but i'll never say that it doesn't matter as much as you think it does. Because it really does influence the sound you choose to make and the decisions you make whilst mixing.