My kids are grown, I have a bit of extra money now, but until my youngest hit 22 my favorite "hobby" was funding their higher education. Until that was sorted, I spent as little as I could on anything like a hobby. Living in the US as a middle class single parent, that was a scary number.I never had expensive hobbies besides collecting way too many knives ...
Bikes? I have a 1500€ bike that the Irish government covered 500€ off. Performs just as well as a 8000€ bike. It’s more about the rider than the bike.
Audio? I couldn’t care less. It’s music. Spotify in car or with AirPods Pro that I got for free (miles my wife accumulated with business travel).
Corona has shown me one thing: what I want to spend money on is traveling. A lot. More. I don’t care much about “things” anymore. Honestly: I’d sell all my knives to fund travel if I had to (and could travel). I’d be fine with a CCK, Tanaka Ginsan and a cheap Parer ...
No bikes, no cameras, not much travel either. I got by with an old wusthoff 10" chef's knife and a mac vegetable knife someone had given me. But what I did do, living in NYC, was to develop a large family dinner crew. I have always made dinners for dozens at a time, very few blood relatives, and my kids got to experience cultures and new ideas at our dinner table. That's still my most enduring, and most beloved, hobby.