You could buy a classified with the same or better reach and same price in 1980.
> Your GDP thing is a complete red herring. GDP has no relevance on the meaning of increases in advertising.
You've claimed that internet cause ad spending to grow. Ad spending only grew because the GDP grew so you can't blame the internet for it.
> Yes it is increasing exponentially
Again, because GDP is increasing exponentially.
Also your graph doesn't show total spend, only the breakdown by sector.