Ask anyone running a general discussion group for a neighborhood. It consumes a lot of time/effort if you do any sort of active moderation. Most people eventually quit if they're not being compensated in some significant way.

On the other hand, if anything goes it can probably be fairly hands off.

> It consumes a lot of time/effort if you do any sort of active moderation

And yet some Reddit mods manage subs with 10s of thousands for… free.

If you want to work for free, Reddit will gladly accommodate.

But they also have thousands of very well paid employees. Average salary $150K+.

Indeed they do. And on that team is a massive number of salespeople who are constantly farming the world for advertising dollars and a large team of machine learning engineers helping to ease the burden of moderation.