You are greatly overestimating the amount of work it takes to maintain a site. Once you get things going, you can do all the maintenance you’ve mentioned in a few hours per year. It’s really not that big a deal.

“Nobody wants to browse a dead site.”

They don’t have to. Regular readers are practically worthless from a monetization standpoint, at least with most monetization models. The majority of the time, they aren’t even targeted.

Restaurants change their menu and apparel shops redecorate because they deal in industries where tastes change. There is unlikely to be a sudden drop in people interested in learning Spanish or sound investing principles, and these sites rank for keywords generic enough that they wouldn’t be affected by whatever was popular at the moment. It works quite well, I assure you. If you aren’t willing to spend 10 hours per year per website to make a load of money, that’s your problem.

As a reader of many sites, blogs and forums on the Internet, I don’t believe that there is such a thing as evergreen content, that never needs updating. Even slowly-shifting fields of interest do move with time. And how will you know whether and when your site needs updating, if you don’t allow regularly some time to explore your chosen subject, ahead of the date when some change will, very probably, be needed ?

Let’s take an example. Teaching foreign languages. That’s a good case in point. It might seem that the way you learn Spanish (for instance) never changes. Wrong ! Languages do change. New words are introduced. Colloquialisms get obsolete. Thirty years ago, people used such phrases as “My tailor is rich” to learn English. There are no tailors any more.

This particular piece of software, which makes the bulk of your site’s earnings, will have a new version some day. You’ll need to review it. Maybe, at some point, this product will start to lag behind a new competitor. You’ll need to be sure to cover this, and update the site accordingly.

Can you say : OK then, I’ll look it up every six months, and update it if necessary ? No, because if some significant change happens at some point — and it will — you can’t afford to leave obviously stale information on your site for months, weeks or even days. Readers would spot it immediately. It would ruin your credibility.

Now suppose that your earnings come not from one, particular, expensive product (which is a very odd situation), but rather from hundreds or thousands of cheap, low-tech products (which is much more likely). Low-tech products do change names from time to time, disappear from the market, get banned because of some new safety rule, etc. Now you have a hundred (or more) products to watch, instead of a single one.

Let’s suppose, for a minute, that you’d be able to find 20 or 30 niches where the content would be truly immutable (which I think is impossible, but never mind). Even then, I believe that you’d have to overhaul each site periodically, just for the sake of change.

After all, that’s what brick-and-mortar shops do. Restaurants change their menus. Apparel shops redecorate. Supermarkets shuffle merchandise around. Even the city hall gets a new coat of paint from time to time.

This need for novelty also exists on the Internet, even if you’re not selling anything. Nobody wants to browse a dead site. Hell, even dictionaries need to be updated in order to keep on selling.