Could you imagine going into the theatre in 1977 and having a dude in a Jar Jar costume, no pod race, a less impressive lightsaber fight and a very complicated plot dealing with trade disputes, senate meetings and midichlorians?
In a word, no! IMHO it just would wouldn't have worked, and I also agree with you that the only reason that the prequels have done as well at the box office as they have is because of the marketing campaign based on the success of the OT. I was born in 1984 and certainly don't consider myself to be old (unlike some of you
), I always ask myself whether there really is that much difference between someone of my age who appreciates the OT and those of a younger age who prefer the PT, it seems to be a very fine line.