From over eight years ago now, Reed Tucker wrote that "The End Of The Comics World Is Nigh".
Overall sales may be getting better (though when you take into account inflation, that's debatable), but in the end, it hardly matters. Comic books long ago became a niche hobby reaching few outside the circle of hardcore Wednesday crowd. The frustrating thing is, DC and Marvel seem to have thrown in the towel on this point, and most everything they publish has become in service of that ever-narrowing crowd.
In Business 101, you learn that there are really only two ways to make more money as a company: You can sell to new customers, or you can squeeze more money from your existing customers. Increasing ARPU, they call it: average revenue per user.
The publishers (Marvel more-so than DC) seem to have decided that broadening the audience just ain't gonna happen, so they've opted for the latter, raising prices and gambling that their current customers will shell out more money each month for an ever-expanding line of branded books or for big events that promise to break the Internet in half.
Do you like Batman? Well, you're gonna love him in 13 other monthly books. Or, were you moved when that one character actually died back in the 1980s? Well, we've got a boatload of shocking new deaths for characters that will definitely not be resurrected in six months with some plot fudge involving a time gun.
Have the following eight years vindicated him? Not really. Sales have continued to increase so clearly the medium term effect of their business decisions has panned out. Adjusted for inflation sales from 2013 ($780 million) have grown to $1.12 billion ($1.02 billion in 2013 dollars) in 2019, for a real gain of 31%. Looks like people really like time guns.
The amount of money to be made off a continuity-contingent story that must be consumed in the month it's published (like Amazing Spider-Man #700, for example) is finite; the amount of money to be made off a story that can be read and enjoyed any time is infinite.
There's a reason why no one puts out soap operas on DVD. After the episode airs on TV, it becomes essentially worthless. It's completely disposable entertainment, only enjoyed during one 60-minute slot on one particular day. Too many comics, especially from Marvel, are similar. Like soaps, they only have one potential revenue stream: the money made immediately upon release. They don't have many prospects in the long-term trade or digital markets. Hawkeye recently became one of Marvel's very rare graphic novel bestsellers, debuting at #9. Most months, Marvel doesn't have any books in the top 20.