When you finally learn how to mix properly, the mixes you produce will sound reasonably good on every system they are played on. It's the amateurs who mix to their "studio" speakers and then play it in a car and are disappointed by the unbalanced mix.

Do you seriously think the big mixing studios have the time to model every single environment where a song might be played? Absolutely not. They know what they are doing and they use one set of monitors consistently. Some of them may take the time to "check the mix" (probably spot checking) on a mono rig. I'm sure some do, but most of them know what they're doing and don't need to, or have the time, to check their work on a dozen different speakers or environments.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.