"So exactly what is "social" justice, anyway? I mean, besides virtue signaling."
Hmm, might want to move into the current world, and learn about more than what net worth means... Some folks even believe in causes other than audio.
I think the OP's question was fine. To me it was more of a "How does one balance all the other normal expenses to achieve the goal?"
Like MC and others, I too packed my lunch every day when I did not need to. I paid off homes early (if financially wise). Cars never floated my boat so I kept the old Acura for 29 years. Luckily no kids/college to sweat. I also carefully bought a lot of good used gear over the years. Finally, as an audio cheapskate, I fortunately had three sets of mint speakers to trade (w/min. cash) to achieve my current used speakers.
I totally get the question; I had it myself in my 30s and 40s when still building towards my current gear. Plan as best as you can; good luck!