That software is free because Apple has a strong incentive to develop a "platform" with which to sell their comparatively expensive hardware. In that context, I wouldn't say people don't realize that real software has a significant cost. That may be the case, but I'd sooner say the market values the software's complements (in this case, hardware, robust compatibility and a healthy development ecosystem) more than the software itself.

One perspective is that people are trained to be too cheap because of market incentives, but another perspective can be even well-informed consumers make a reasoned pricing decision that concludes with free or low cost software. And if you want to make a normative point, you can say that this is bad for small companies trying to make software for these consumers, but you can also say that consumers are benefiting more by purchasing the software's complements rather than the software itself.