It's kinda hard to get across what I'm trying to say. In quantity, yes, without a doubt there is more advertising today than there was a long time ago. That's a fact. When I say pervasive I mean how much it infiltrates a person's life in terms of how many things that person is exposed to.
Back in the day people were exposed to MUCH less information and stimuli, but the little they got was incredibly influential in how these people led their lives. Posters, flyers, newspapers, these all existed back then and they all had massive amounts of advertising. The thing is, those few mediums and the influence they exerted over people back then are comparable in proportion to the influence being exerted by advertising today in the myriad of formats and mediums available. When you take into account the amount of overall external information available back then, and the overall external information available today, you'll see that the percentage of that information that would be classified as advertising is about the same in both.
Personally, I think a lot of advertising is fucked (and I work in advertising). However, I do not think that the evils being attributed to it in this thread are part of some secret conspiracy masterminded by some global conglomerate. I think it's more of a consequence of the nature of advertising rather than a set goal of the industry. This is an industry where in the end, the client rules, and clients are too busy trying to lure consumers away from their competitors to really come together and lay out such a plan. Overall, yes, they definitely do want to keep a consumer culture going, so that's a factor, but they play nice with each other much less than you'd expect.
Right now the advertising industry is undergoing some serious radical changes due to the change in lifestyle of the consumer itself, because a LOT of people are saying "fuck advertising" and they are now empowered with the ability to do something about it. Believe it or not, we as consumers have more power than you think. I think you're gonna see some changes in the next decade where advertising is going to be something you actually have to go look for, instead of advertising looking for you.