On Strips: The Original Graphic Novels
Obviously, all of these different venues were ways to try to capitalize on McManus' success on the newspaper page and, naturally, some were more successful than others. But it's fair to say the reprint collections were decidedly on the more successful side of things; ultimately, there were 26 books in the series, carrying up through 1934. That should hardly be surprising considering they were the closest and most faithful adaptations of the newspaper strips that generated all the popularity in the first place. (While the books reprinted the strips, they were reformatted slightly for a stacked presentation rather the original linear version.)
Rick Marschall recently pointed out to me that strips such as Bringing Up Father were obvious to collect in bound editions like this. By that time, many comic strips had developed a day-to-day continuity which made more sense to read in larger chunks. It was something of a no-brainer for a publisher to realize this, and find a way to re-present significant portions of a daily strip at once. Cupples & Leon repeated the same idea with Little Orphan Annie, Barney Google, Mutt & Jeff, and others. Because all of those other strips had developed ongoing continuity. It was hardly uncommon by then.
It goes back essentially to the dawn of newspaper comic strips. Although many of the dailies could be taken on their own, Hogan's Alley/The Yellow Kid occasionally featured stories that continued from one day to the next. Continuity was almost baked into the very medium. So by the time of the so-called birth of the story strip in early 1929 (when Tarzan and Buck Rogers debuted) it was actually an old-hat idea; all that was really "new" were genres borrowed from prose works.
With this notion of a continuing story embedded in the comic strip, and seeing the success of the collected format, it's hardly a leap to try that collected format but with new material. The first comic books.
Despite the success of bound books like the Bringing Up Father one shown above, publishers generally opted for the pamphlet format. Although I haven't researched this portion yet, I suspect we saw more floppies than graphic novels because of the price point and the unknown characters. Where a consumer might be willing to spend a dime on a 50-page booklet featuring a bunch of characters they don't know, would they be willing to part with a considerably larger portion of their income on an unknown quantity? Indeed, while Lynn Ward's Gods' Man was very well-received and went through two reprintings within its first four months, Milt Gross' He Done Her Wrong sold very poorly. Publishers would no doubt be leery of seeming crap-shoots like that.
Comic books, being considerably cheaper, would have been more open to purusal as readers got to try out the likes of Superman, Chuck Dawson, Zatara, Sticky-Mitt Stimson, Pep Morgan, and Tex Thompson all for one dime. Publishers could more readily keep throwing ideas against the wall to see what stuck, without committing an entire 300-page novel to one big question mark. So comic books were, in effect, designed as graphic novels but at a less risky price point. And newspaper strips, with their often heavy reliance on continuity, were just graphic novels before they had the right format for them.
Just something to put the medium as whole into a slightly different perspective as you launch into your weekend!