Whats a hobby/craft that you wouldn't expect that has an incredibly high ceiling either monetarily or in sheer skill?
For example, I'm sure the average joe doesn't know just how expensive calligraphy pens can be, or how deep the rabbit hole goes on video game speedruns.
True. But also equally true if you do buy equipment and indulge in every temptation. There is absolutely egregiously expensive gear in all shapes and forms.
Ah yeah the gear goblins are real I swear. They keep telling me I absolutely need a 6-string fretless to get good and I think they might actually be right you know, it just makes so much sense. Why waste time limiting myself to 4-strings. But they also think I'm too dumb and will have to get a 5 string before, I really need to take baby steps after all... Ahh well, it's not like I needed that 5k anyway.