I'm not so sure that the average person won't care. They are increasingly aware of how much they pay for data on their phone plans, and how crossing limits decreases their speeds. After a big bill or two, people start looking for options.
The power of default settings is huge. Perhaps you're thinking of yourself or your peers.90% of the rest of the population just doesn't care about these issues.
Source: http://fortune.com/2015/06/16/apple-google-maps-ios/
However my supposition is predicated on the continued restriction of data and speed by carriers. If any new business model comes along that upends that, then I suppose Americans won't become data usage aware.