Way back, some restaurant decided to give free bread to customers who ordered a meal. (Maybe it didn't really happen that way, but it could have.) Since its prices were about the same as everyone else's, people went there for that reason. The profits on the added traffic more than offset the small cost of the bread.

Other restaurant owners watched this happen. Pretty soon they all gave free bread. It became a competitive non-issue, though some restaurants got good reviews in InsideEater for their fine bread. It was an added expense for all restaurants. Prices were raised to cover the cost of the "free" bread, so restaurants didn't lose. The only losers were those who didn't eat bread, but had to pay for it anyhow since the few restaurants that didn't offer it tended to have inconvenient hours, a limited menu, or some other drawback.

Same thing here.