There is a level of success in the current literary marketplace where word limits no longer exist. You can see it in many a novel series, as the first books are a fairly reasonable length, then later works meander on and on, giving fans more and editors less to do. Digital books have added an egalitarian aspect to the trend, and the massive novel is everywhere.
This isn't to say that the massive novel didn't exist before this century, but when you look at The Complete Sherlock Holmes filling one thick book with four novels and fifty-six short stories, one has to wonder if all those added pages are worth it. Conan Doyle, as we know, wasn't that fond of Sherlock Holmes and treated him a bit like a trip to the bank as time went on -- get in, do what's necessary to get the cash, get back out again. There was never any worry of Conan Doyle dying before he finished anything, as he finished Sherlock Holmes about four or five times.
And it makes you wonder: Would we treasure Sherlock Holmes so much if he had appeared in a sixty-novel series, with at least four of them being epics perhaps worthy of trilogies?
Conan Doyle packed a lot of depth into what he did write, with details and descriptions that Sherlockians have digested for a hundred years so far. (Almost like the fandom is a Sarlacc Pit, and Sherlock a poor Boba Fett.) It's a quality meal worth savoring, not a massive buffet that leaves you wondering what you just went through and why.
Would Conan Doyle be the same writer in the current marketplace? Would he go all J.K. Rowling as the Sherlock books became more popular, eventually giving us a massive-tome version of "Shoscombe Old Place" with tent camping and the actual trout fishing alluded to in the tale? Would The Hound of the Baskervilles had a second half all about Sir Hugo, just as A Study in Scarlet did about Jefferson Hope?
Doyle wasn't so thrilled with Sherlock, so it's hard to imagine him spending all that time writing an eight-hundred page novel when he could get away with a quarter of the length. He'd try screenplays, of course, just to get the cash-to-words ratio maximized as he did as little with Holmes as he could, perhaps, but we recall how well his ventures into theater went. Maybe movies wouldn't have been his thing. (Unless it turned out he had a talent for directing.)
Conan Doyle was such a master of doing more with less in his prose, that it's hard to imagine just where he'd wind up in the current market. Could he single-handedly bring back the short story? (Is it gone? It seems like it is, commercially.) Or would he pull a George R.R. Martin and let HBO finish out Sherlock for him until he got around to it?
It's an entirely different time than when the Sherlock Holmes stories were first published, and one does have to wonder.