DC had been pushing for comic books in a larger, more expensive format since the 1970s (regardless of paper or printing quality). You could say they saw the handwriting on the wall. Actually, all of this goes back even further to the 25c "80-Page Giant" comics format of the 1960s. Even as a kid I would choose a Batman 80-Page Giant over a couple of regular 12c issues, same for Marvel with their reprint titles like Fantasy Masterpieces/Marvel Super-Heroes or Marvel Collectors' Item Classics. Of course, that presumes an interest in older comics, but except for the Golden Age reprints in Fantasy Masterpieces and the DC Super-Specs, most of the stories reprinted were only about 5-10 years old, although if you're a kid, 5-10 years is a lifetime. I always felt that any comic I hadn't already read was "new" to me. Later in the 1970s, Marvel seemed to abandon the more expensive format of reprint (or partly-reprint) titles, while DC kept pushing with the 100-Page Super Spectaculars and later the Dollar Comics line and things like Action Comics Weekly. They forsaw that trying to make up the difference in overall profit by just continuing to crowd the rack with more and more titles at the cheapest price point was leading to an inevitable downward spiral in sales. You can only divide the total marketplace up into so many different fractions. Publishing fewer titles with more pages at a higher price point, and trying to woo an audience of loyal readers that way would have been the better way to go (and indeed, that's exactly the way the Japanese comic market DID go). At that point it became a battle of the mainstream consumers against the hardcore collector/readers, and we all know where that ended up, as the mainstream distribution outlets didn't want to bother displaying dozens of new titles each week for pennies worth of profit per copy sold. I can recall as far back as the 1960s, there was one local pharmacy that would only carry a few of the top-selling 12c comic titles like Superman and Batman, but MOST (since there weren't really that many) of the 25c giant titles, because they made twice the profit for every copy sold. Anything less than the best-selling comic titles was just taking up valuable rack space that could have been devoted to more profitable publications (in other words, NOT comic books).
The thing about these "Giant" titles was that they were all anthology titles where you could get at least 4 (and sometimes up to 10) different stories, so in that respect they were a return to the original concept of the 68-page 1940s anthology titles like Action Comics or Marvel Mystery Comics. Japanese manga weeklies or monthlies never abandoned that anthology format, and instead just continued to add MORE pages of stories until the typical ongoing manga anthology title was 200, 300 pages or more. Those older American giant comics were sort of like the "trade paperback collections" of their time, though. Even today, DC is going back to doing some mainly-reprint tiles (the 100-Page Giants of the last couple of years) with partly-new material. Actually, they're a pretty great deal in terms of page count, with a cover price of $4.99 (only a buck more than their mainstream line of titles, which offer only about 20 pages of story for $3.99). The idea is to get these back into mainstream outlets like Walmart, to entice new readers to get interested in comic books. Except for hardcore collectors, the current floppy comic book format of 20-page stories for $4 (20c per page of story) isn't perceived as good entertainment value for money by the average consumer, especially with so many other entertainment options available to them.