This is a poor point because, like Digi admits in his own video, he has absolutely no idea what Japanese numbers are like and production committees (who are the ones who decide what shows to greenlight and get money and how much) look almost exclusively at the domestic market.
Yes the foreign market has been growing more in recent years but it is a tiny, tiny, TINY drop in the bucket compared to the Japanese market.
Shows that are not popular on MAL (which is pretty much 100% only registering foreign opinions and not domestic opinions on the shows) can still be profitable and make money. MAL ratings and viewership has zero impact on the actual sales the show generates in media, merchandise, etc. in Japan, which for all intents and purposes, is the only market that matters to production committees and publishers/studios/producers.
The Japanese market for anime/manga/media in general, but particularly for these medium to low budget anime that aren't expected to be blockbusters, rely heavily on whales.
When disc sets of anime, figurines, various other merchandise, or a set of the associated manga/light novels can bag several hundred if not thousands of dollars per customer, you suddenly don't need to actually please that many people to make an anime solvent.
There's also other ways that production committees make money in Japan, like TONS of events, cross promotional sales (people who don't live in Japan probably haven't seen the ridiculous amounts of cross promotion done for all kinds of anime or books), licensing the brand or characters, music sales, concerts, special appearances on TV or internet shows, etc.
I don't know how familiar Digi is with the Japanese market but it seems like he thinks that he has "make anime super successful" thing all figured out (and seems to be saying repeatedly that if only the anime studios/producers would listen to him, then they would be soooo much more successful) when the industry is extremely mature and knows plenty of ways to make money and achieve their goals.
Does this mean they're perfect and there's no room for improvement? Of course not. But Digi seems to just be painting them as blindly ignorant and himself as having the perfect solution when he seems to be working from a huge disadvantage in terms of information. He doesn't have years of statistics, sales data, demographic research, nor does he intimately know the circumstances of the players in the industry that need to be worked with to make anime in the first place. I find this a strange position to be lecturing from.