Ahaha..hahah..I'm actually doing an academic research on this topic, so I can rant a whole page about it, but I'll try not to. There are so many logical fallacies and misunderstandings in his terminology that I don't even know where to start.
First of all, his arguments are based on Google Trends. Google Trends only show interest, in how many times people look for term. The problem with the manga industry does not lie in the lack of interest, it lies in the distribution and culture. There is a big demand around the world, but most readers are still looking for scanlations which does not contribute to the industry in any monetary way. Since scanlations are free and more up to date than the legal sites, it's a problem that is still hard to tackle. Some mangaka don't want their works to be translated (since the English speaking audience can be such a bully, I've heard) and some publishers don't want to tap into the English speaking viewership since it's a big risk. The risk is real as someone from Manga Planet explained how much revenue the manga industry gets in Japan only in comparison to that in the US eventhough the US got a bigger audience (logically, with bigger population). I think it was about 4x the US? The problem is that manga in Japan is more common to read compared to comics in the US. This is without even talking about the outer competition such as webtoons.
Anime and manga are interloping industries, but they're separate. He talks about how it is not a future of anime and then goes on to compare it with manga. Nope. Then goes on to use Korean manhwa in place of webtoon. Another nope. Manhwa is just manga as it is just a translation of comics in English. Sure, nowadays it comes with a certain style assumptions and expectations, but manhwa is facing the same problem with manga. People are going digital. This is where LINE (the global subsidiary of Naver) Webtoon comes in. But even Korean webcomic creators are still facing problems with going global. Here's Mr.Comics (formerly Manga Rock)'s article on it.
I'm not sure if he knows that Webtoon is a platform, because I think part of why the community kind of merge slowly is the exposure they receive from having the same platform. Even in Tapas we have a variety of styles and you can't exactly limit yourself to just manga style or manhwa style or ligne claire style. But at their global launch, of course it would be more exciting for new readers to already have many titles you can read from the get go. What titles do they already have license for? Korean webtoons. So the Korean webtoons now gain popularity. What comes after popularity in the comics industry? Adaptation.
It might come as a surprise for Mr. Burrowes, but South Korea plays a big part in the industry of animation. A LOT of Japanese anime actually got co-produced by Korean studios (Mainichi Kaasan, La Corda d'Oro, Rurouni Kenshin, Yu-Gi-Oh). Even American animations got sent to Korea (Ben 10, Dead Space, He-Man!). And yes, they do have their own titles, it's just that those who are only into Japanese animation won't look for it. But now that the Korean webtoon titles got English speaker fans, word got out if they're going to be adapted into anime(ation). Fans rejoice. Mr.Burrowes burrowed his eyebrows.
I do have to agree that manga will not lose its future to manhwa, but more because the readers expect to read about Japanese (cultural, historical, a whole different story for another time) and because its future is in digital. Here's a screenshot of AppAnnie's Top Chart Matrix for iOS in the Books category:
Japan's Top Free and Top Grossing are all manga apps: Pikkoma, LINE Manga, Manga Park, Meccha-komikku, MangaBANG!, Shounen JUMP and Comico.
No comics-related app in the UK and only Tappytoon in the US. Tappytoon is another webtoon reading platform from Korea. So it is safe to say that webtoon is gaining popularity in the US (readers just don't use Google search to get to it).
Lastly, he's surprised by a Youtube video title. It's YT. Of course it's going to be sensationalist. It's good enough if it's not a click-bait. Calm down.
But then again, maybe his article is also a click-bait?
Damn.