Could my parents afford an iPhone? No of course not. Among many other things. $$$ isn't the only quality of life indicator. When doing this calculation, you of course adjust for these things. an iPhone would cost billions of dollars in 1970. Is that the figure we should use? Probably not. But it means that these calculations are largely arbitrary since we don't know the true value of an iPhone to a person in 1970.
All this stuff is conveniently ignored when comparing against previous generations.