But people are spending far more time on their phones today than they were 5-10 years ago. It shouldn't be a surprise that they're spending more money on their phones, accessories, telecom service, apps, etc. than they were 10 years ago, regardless of what their salary is, since the phone is involved in more aspects of their life.

For what it's worth, if you want to use your phone in exactly the same way you did 10 years ago (occasional short voice calls), you can do it much cheaper today than then, with a TracFone.