Yeah, that’s not the case - although it often sounds like it, perceptually.
Imagine a kick that for some reason is a pure sine wave at 40hz. No high harmonics or click, just that fundamental tone. If you have a speaker that sucks at low end - say, a mobile phone speaker, a small Bluetooth speaker (and it’s not because they are bad, it’s because they physically aren’t large enough to deal with stuff that low; the wavelength of a 40hz sine is a bit over 2 metres) - you’re not going to hear much. The same kick with a bit of click, or harmonic richness - noise, say: you will hear more of the high end on a crap device, but you’ll now also know this there.
If you’ve even been in a place with someone listening to dance music on a phone and it sounds… passable… a lot of what feels like “low end” still has a bunch of higher information in. It still sounds better on a good sound system, it just doesn’t disappear on a bad one.
So sound design and choice is part of this. (I am convinced that some of the “sound” of a lot of EDM in the last 15 years is because it sounds good on crap speakers as well as clubs)
I’ll also be honest about “how bedroom producers sound like this”: mixing is a per-track thing, and a lot of bedroom producers, esp in things like house, are working entirely in software where this is borderline free, processor-wise. Not many of those tracks are the raw stereo out of a single box run through light mastering.
(I know many people on this forum make a lot on nothing but hardware, but live sound and mixed sound aren’t quite the same vibe, and a lot of people are still recording and mixing in multi track).
So 1) yeah, for the sound you’re interested in, more detailed per-track mixing might be good. But you can also get a long way with sound design tweaks, and that Base/Width filter is ideal for thinking of as a “place in the mix” tool.
You might also find engaging in stereo mastering, possibly with an engineer, an interesting exercise.
and 2) at the same time, this isn’t a numbers game. It’s a what-it-sounds-like game. You’re not mixing in Excel. So some of the work will be building experience. Sit down with tracks you like and just listen, in great detail. Why do they work? What’s special about that kick? What can you hear? How could you copy it with what you’ve got? And then listening and fiddling til you like your own things.
Sound is quite relative: you have to adjust what you’ve got til it sounds how you like, which means you can’t just set your mixing and processing chain to the same numbers and be done.
See, lots of words to say ‘it depends’. As you build experience, you’ll go faster from “I need to change something about the kick” to “here are the settings/adjustments I should make”. But you’ll always be ping-ponging between the land of listening/aesthetics/vibes and numbers/faders. Over time, you just ping-pong faster.