Oh. I didn't think of that. I Germany the tax for beer is just 5% so it wouldn't change that much.

From the article:

Most breweries use one of just a few basic options for production, each of which comes with its own set of considerations. There’s dealcoholization through evaporation, aka vacuum distillation, in which beer is heated and distilled to remove the ethanol. Dealcoholization via reverse osmosis, meanwhile, uses membranes to separate the alcohol from the rest of the liquid. The former method can strip some desirable flavor compounds, and both options are a financial stretch for smaller craft breweries.

Emphasis on the last line. So yeah it does add some significant cost. Which is why they resort to cold-contact brewing which can result in worty/bready taste as the article notes. So if you want good NA beer yeah, it's more expensive probably because they're using all the same ingredients and then doing the extra process. Obviously there won't be the alcohol tax though.