People may be buying stuff after they pirate it as a "demo" of sorts, but there are still others who get their stuff solely via illegal downloading or scanlations, and, I don't mean to turn it into a "businesses are greedy!" thing, but they still lose money with every person pirating and not buying. Plus, some people may not take it well that things they've made, such as music, art, and games, are being illegally distributed despite the hard work they've put into it. That and/or they're not getting money back to continue making stuff they want to keep doing.
I agree. Like or dislike, piracy is a trouble. Do you want an example? In a message board of a certain anime series people spent YEARS whining about anime-publishing companies not releasing their favorite series and not giving it any chance because it is old. All of sudden it was announced that series would be officially released in DVD and Blu-Ray. Their reaction? They did not want to buy it because they had already downloaded it. Oh, sure, they gave several excuses (such like it being too expensive or disliking the dubbing... before nobody knew anything about the pricing or the dub work), but they always added "I will stick to the pirated version", proving that their "reasons" and "arguments" were only excuses.
But what about the people that checks a manga online, and then decides buying it? And what about classic manga series? There is a lot of people is only aware of them because a lot of them are available -and free- online. Otherwise they would not give them a chance because they look "old". <snorts>
That is the other side of the coin.
Right like someone else said, you should not be concerned about manga sites disappearing or about reading online series such like Naruto, One Piece, Attack on the Titan or the newest Flavour Of Month. There will always be pages hosting fantranslations. You will always find them. No, I am concerned about classic manga and hard-to-find series. Many current pages host classic series, and should they close, those works can become impossible to find online, since newer sites can preffer hosting the newest shiny stuff only, since many newer fans are only interested in the new flavour-of-month, popular series and they could not care less about the classics ("I am not used to this art and/or storytelling style, therefore it is bad" "It is at least ten-years-old, therefore it is old and it MUST be bad"). Manga sites shutting down will be detrimental to them.
I wonder if companies should not consider another bussiness model (and publishing best stuff) instead of blaming the manga readership dropping on piracy.