At least in PHX, I’ve been seeing a lot of businesses with a 2-3% surcharge for cards
On a €600 laptop or desktop we'd earn maybe €50 to €75. The €12 is a comparatively large fraction of that. We didn't actually make that much more money from more expensive laptops, so for a €1,000 model we'd typically also earn €50 to €75, and with €20 of that going to Visa... yeah. After factoring in costs for sales, warranty, rant of the store, etc. there is not much left.
On one hand you can say "well, it's only €20", but on the other hand if everyone started paying paying by CC we'd pretty much go bankrupt.
The only cashless place I’ve seen around here is the major sports stadiums, everyone else seems to greatly prefer cash over cards.