Not true. You have to look at numbers. All forms of advertising have what is called a CPM rate or 'cost per thousand' (m is Roman for 1,000). While a blimp might have a better CPM ratio, it isn't targeted at all. In fact it is the least targeted form of advertising because it only gets seen once, and the audience is wide, not narrow.
I work in radio. I have a minor in marketing. You don't need to spend millions of dollars to be effective.
I COULD WIN NASHVILLE for Ron (Fred's home town) if I had $500k or less and that includes all of the advertising I mentioned above except for of course a blimp. I can probably do it for $200k (in fact I'm going to try - more on that later)