If you're an actual pro, you need your stuff to work properly, efficiently, reliably, when it's called for. When you're a hobbyist, it's sometimes almost the goal to waste money and time on stuff that really doesn't matter beyond your interest in it; working on the thing is the point, not the value it generates. Pros should spend money on good tools and research and knowledge, but it usually needs to be an investment, sometimes crossing over with hobbyist opinions.
A friend of mine who's a computer hobbyist and retail IT tech, making far far less than I do, spends comically more than me on hardware to play basically one game. He keeps up to date with the latest processors and all that stuff, he knows hardware in terms of gaming. I meanwhile—despite having more money available—have a fairly budget gaming PC that I did build myself, but contains entirely old/used components, some of which he just needed to get rid of and gave me for free, and I upgrade my main mac every 5 years or something. I only upgrade when hardware is really getting in my way.
It's interesting that you chose photographers as the example here. In many cases that I've seen, enthusiast photographers spend much more than professional photographers on their gear because the photographers make their money with their gear and therefore need to justify it, while the enthusiasts are often tech people, successful doctors, etc., who spend lots and lots on money on their hobbies...
In any case, your point stands, that "enthusiast" computer users would easily spend $3-4K or more on gear to play games, train models, etc.