It is not a new problem, but the Internet has made it more visible. People have always created wealth and production that is not part of the market economy, and so is not measured. If you take care of your own child, clean your own house, grow your food, fix your car etc it is not part of GDP, bit if you hire it done it is. When students study, learn a skill, or a researcher creates a new knowledge it adds wealth, in the sense that it creates a productive resource, but does not show up on anybodies account as wealth. The government statistics counts both public and private education expenses as consumption not investment.
You could even argue that most of the wealth we have inherited from our ancestors that provide us with a good life are things that are not now and never were bought and sold in markets.

There is an often quoted saying ” if you give someone a fish they eat for a day but if you teach them to fish they eat forever”. The logical conclusion of this is that the knowledge is more valuable that the product.

It’s interesting question and I never think about it before.

I’d say that every contributor of Wikipedia feels a very personal achievement that can’t be measured monetarily. It’s similar like faith.