Whereas if I drove every day, and would spend a lot of time in the driver seat, I'd be much more inclined to buy something nicer (as opposed to merely functional).
In this case, photography is important to me, and I spend a lot of time doing it - so it's important that I have a tool that not only works well, but feels satisfying to use. After all, it's not a very good hobby if I'm constantly being frustrated by my equipments' usability.
Likewise, it's important for me to have a really nice coffee mug - given that it's part of my daily routine and I spend a lot of time interacting with it.
What I see is that many people over-optimize and fail to account for this effect - and they skimp on things that they do use heavily, resulting in a quality of life loss that they're probably not even aware of. (e.g., daily commuters, people who spend tens of hours in a car weekly, but driving a "good enough" beater, when they can easily afford better... or hackers who buy cheap/poorly made keyboards/mice even though they spend hours with it every single day).
On the point about the cameras. If the photographer has a decent level of talent, then the gear definitely matters. Less so if they don't.
I know a lot of gadgety people who like to show off their expensive cameras. Their photos, however, aren't worth showing off at all - it wouldn't have mattered if they used a 5DMK2 or a lowly Rebel XSi. Boring is still boring no matter how sharp the picture is.