Do you mind giving a ballpark of how much you make? I was under the impression adsense basically made you close to nothing, perhaps unless you had millions of monthly unique visitors.
Earning from Adsense depends on number of factors including the Cost-per-Click (CPC) and Click-through-Rate (CTR). If you have content based on high CPC keywords and get traffic from western countries, you can make a decent earning.
For example, if you serve 10,000 page impressions per month with average CPC of $0.50 and a CTR of 3%, your monthly earning could be $150.
In a lot of countries (ex. Belgium, where I'm from) that is not a decent income. Not even close. So you'd have to have a lot of those niche sites to earn a (self-employed) living.
I run two blogs that i kept updating over the years. I don't post frequently, maybe once a month. I earn around 100-150 euro a month from them. It's not much but think of it as pocket money - its a zero effort income - especially if the topics you write about genuinely interest you.
It is supposed to be passive income, so yeah, you have to build a lot of such sites (or a few with high payouts) to replace your regular /salary earnings.
Yeah, that falls into the "just work a few extra hours in the day job and save yourself the hassle" category... Good to know that's how the numbers stack up.