I don't understand the inference made by Gary Greenbum that data...

I don't understand the inference made by Gary Greenbum that data is relatively cheap in developed countries like USA and Australia etc. I currently get 1.5 gb on my $95 plan with Telstra and every 1 gb thereafter costs extra $10. How is that cheap ? 1.5 gb is only enough for reading HC IMO. If I watch any videos that will be spent in a few days - luckily most of my iPhone usage is done with wifi at home.
I went to Cambodia and the cost of data there seems cheaper than here. Although in relative terms the average wage over is something like US$250/month or $1 per day.