What a great resource; thanks for posting that.
I like to refer to this article on this site:
How Much TV Commercial Length has Grown over the Years
But two things jump out:
1) The amount of commercial time is virtually unchanged for ~the last decade.
2) The first entry, for 1952, is qualified as "time watching commercials".
Obviously, that technology matured. Betamax changed everything in 1975, and Tivo changed it again in 1998. Now, the Hopper skips the commercials for you.
So the "time watching commercials" has probably not increased at all. The amount of commercials has definitely increased. The time spent watching them, probably not so much. I know my time watching commercials has been close to zero ever since I won a Betamax in a contest in 1977.