I have tried multiple methods, from running network ads and affiliate ads to selling products and services. However, nothing has worked for me as well as Google Adsense. I make money form Google Adsense from half a dozen websites.
I think any community should aim for at least net zero cost (income covers basic hosting) to make it sustainable.
Ads are only useful if you have a lot of existing traffic. If you are a smaller site but high value, you may want to think of direct sells or subscriptions. As long as you provide something of value, users will appreciate.
I run my site as a resource for the community. I fund it totally out of my pocket and don't expect the community to support it currently. If it grows to the point of costing several hundred dollars a month to support the site, then that will most likely change. But I honestly don't see that anytime in the near future, so I'll continue to support it out of my pocket as an extension of my current hobby.
You have two types of admins
Those that want to provide functionality and knowledge to the public, even at a cost to them
and then
Those that want to make money off their sites.
Sometimes that second intercedes with the first... but generally that's only to make enough to cover the costs... not to make a "profit" and support their lifestyle from it.
It ultimately turns on what the admin has as a target for their site... a money maker, or an information distributor. Unluckily many are more in the "show me the money" brigade.
I made money around the year 2011 with employment sites. It was a few hundred USD a month. Anyway, I haven't made money since then on sites, but I didn't go back into the employment niche.
I make $0.00 from my site because it is nothing more than a hobby for me. Since I use free software the only thing I pay out of pocket for is the domain renewal on a yearly basis.
I'd rather build a different site (and niche) for making money, unless, of course, I make some paid classifieds section and targeted traffic massively increases.
Note: for the drumming niche, I don't want ads cause it annoys people. I mean, it's enough that they're on a third party site I use also.