I just know a lot about audio, find it fascinating, and enjoy answering questions and helping people. In doing so I help myself in the process. Because, writing concise informative answers calls for having ones thoughts in order, and writing as with most things improves with practice. So I get better at both. Plus I had a lot of time to kill at work.
Now being retired I have actually cut back a bit.* But the quality is higher. This is a big plus. The people I want to help get helped even more, and the people I don't their heads explode even more. Audio you see is not a zero sum game. Do it right and we all win.
*As millercarbon. Posting as my other 13 aliases is turning into a full time job. By the way have you noticed Tsushima, nonoise and fuzzball never post at the same time as me? Think about it.