I've heard a million stories about their horrible quality control in recent years, and their prices are outrageous. They're putting out guitars with serious fit and finish issues, often playability issues, that cost as much as Fender Custom Shop stuff. Morale within has been notoriously low for years (seriously read glassdoor about working at Gibson, it sounds like a nightmare). See also endorsers jumping ship because they can't be bothered to listen.
Plus apparently their minimum buy is outrageous if you want to sell them, to the point that many mom n pop shops have had to drop them entirely. And on the side they're trying to be a general consumer electronics company. Sure, guitar-centric music isn't the all-encompassing cultural juggernaut it once was, but people are still buying and playing guitars. Plenty of them.
This isn't that hard. Follow the Fender plan. Sell versions of all your iconic models at basically every imaginable price level, and take advantage of the advances in CNC to deliver really high quality instruments at a price point previously undreamt of. By all accounts, Epiphones are pretty decent. But you gotta get people talking about them the way they talk about Squier Vintage Modified - having their minds blown by the professional-quality instrument they got for $300. You can still sell $3,000-$5,000 guitars to a tiny number of people, but the boomers are dying off and millennials are poor as shit. You have to make it where people can buy an LP worthy of the Gibson name for like $600. And you definitely can. Other people are doing it. The "Standard" Les Paul should not be $4,800. And when you're asking someone to pay $4,800 for a guitar, it has to be perfect. It has to be beyond perfect.