like yes i obviously know why this philosophy exists and why people say it so much, and yes, there is validity to it. but it only makes sense as a way to confront one specific situation: the neophyte artist who first put paint on canvas two weeks to a year ago, finds their work unsatisfying (insert entire ira glass "killer taste" quote here) and has come to people they consider Better Artists to ask "am I using the wrong brushes?"
yes, it's valid to reply to that person by saying that, you know, da vinky could still have painted the mona lisa with a house painting brush dipped in cowshit. that's true and poignant, but people love to throw this phrase around the same way forum nerds use "RTFM", as a shutdown to any and all questioning about technique and tools, and that's where it becomes insulting, dismissive, and often just wrong.
i cannot tell you how many times i've seen someone reply "RTFM" to a question that is not answered in the manual. and I cannot tell you how many times i've seen someone ask about technique or tools and get told "just try harder sweety :)" tools matter beyond an objective measure of quality.
yes, two paintbrushes may be "basically the same", two pencils might be "basically the same", and a skilled artist can notionally produce anything they like with dollar store versions of either one. but a brush with a particular texture lends itself to specific kinds of results, and even as an extremely inexperienced artist I can tell you that there is a massive difference between shading with a #2 Ticonderoga and doing the same thing with a Blackwing. they are "the same", but they aren't the same.
but that's not even the sort of thing i'm talking about. i'm talking about people insisting that DSLRs and smartphones can readily take the same pictures, or acting like "what guitar do i need to make speed metal" is somehow not a valid question (it's an ibanez RG, you want an ibanez RG.) or even worse, people suggesting that music or art software is all interchangeable.
christ. christ almighty
an artist COULD make the same picture in photoshop and krita, but if they aren't straining as hard as they can to consciously make that specific image, the software is going to heavily influence the result. a musician COULD make the same song in ableton or FL studio or reason, but if they are starting from scratch and working organically it is very likely that that won't happen. and that's only considering the physical structure of the various UIs and how they push the creator towards specific ways of making and using patterns and automation, not even considering the likelihood that they're using a completely different set of tone generator plugins. nobody would say that a trumpeter would still be a trumpeter if they bought a clarinet instead of a trumpet.
my videos wouldn't even look the way they do if I was still using goddamn Adobe Premiere, because while they're both notionally NLEs, the visual effects that are readily craftable in Resolve are very different than in Premiere. and like... canon cameras shoot redder than nikon. yeah, you're gonna swim against that current, you're going to recolor everything in lightroom anyway, but the fact that every one of your pictures is just warmer than the same picture shot on another brand of camera, and in ways that are not fully and automatically corrected by dragging the color temp slider, fucking matters. don't get me started on film stock. art is inseparable from the tools used to make it.
and i mean... all of this is also ignoring the simple fact that it's often nicer to use better tools, and if someone asks "what's the best tool," you could just... tell them? and let them waste their money on it and learn a valuable lesson in the process? answering a question with a brand and model is literally easier than replying with a scolding, every single time. it's free.
After 15 years of doing photography, and collecting a decent amount of cameras, I've reached a point where it doesn't really matter which one I pick up and use to make photos. I'm getting at least decent results out of any of them. I have my favorites for certain situations, but I like the challenge of trying something different and making it work.
However, it's also terrible to tell a beginner that the camera doesn't matter. I got there by first getting a compact digital camera, then a DSLR, a SLR, a Hasselblad and then a Leica M4. All over the period of a couple years. Each one taught me something about photography and made it possible to effectively use the next camera. I needed that experience to be able to use a wide range of tools.
If you'd ask me what's the best camera I own, I'd probably say my Hasselblad. But telling that to a beginning photographer is like telling that a Lamborghini Countach is a very good car. Like yes, it's kind of true, but the ergonomics are not good, it has risen in value to such an extent that using it is a bit nerve wracking, the consumables are expensive, and maintenance is even worse. It's an acquired taste.
So the answer I give to the question "Should I get a better camera, and which one?" depends on the experience level and budget of the person asking. It will boil down to: this tool will help you grow to the next level. There is always a better answer than "It doesn't matter", or "The one I'm currently using".