A few things first: Nate brings up an example that I wouldn't have, which is that there are really two anime markets and we have to be careful about conflating the two. There's the one for kids, made up of your Precures and Aikatsus and Cardfights and Shounen Jumps. This market is enormous and just by sheer numbers alone is guaranteed to outstrip anything in the US. The other market is the late-night market, which operates slightly differently and is the market that targets the otaku. This is where the mature anime will sprout up. Presumably, when we talk about foreign influence, we're talking about being tastemakers in this slice of the market.
Now, on to the chart. At first glance, it looks impressive, but we need to think about what is actually included in that delicious looking pink slice. I
do not believe that Japanese reverse-importing makes up a significant portion of that slice. For one thing, like Ante brought up, reverse-importation only really started making sense once North America and Japan were put together in Region A for BDs, but that's a post-2008 phenomenon and the pink slice actually shrinks after that. (Also, North American releases suck compared to the Japanese limited editions)
I also don't think that Overseas means North American disc sales. It'd make no sense if you compared those numbers with the domestic breakdowns. And so now we need to remember that Overseas means 'not Japan' which consists of a lot of places that aren't North America. Children's anime is a lot more mainstream in countries around Japan: HK, Singapore, Korea, Taiwan, etc. These are huge markets and arguably larger than the US. So a charitable interpretation of Overseas would be all licensed media (disc/TV) across all territories which does not include merchandise. If we do include merchandise, then the Overseas slice becomes kinda pathetic. However, another question is whether they're including Overseas
imports of Japanese discs, which would further reduce the licensed sales slice.
So now, if we want to talk about influence, we can cut up the Overseas slice into a few broad demographics for our purposes: Asian children's, Asian late-night, EU children's, EU late-night, NA children's, NA late-night. Assuming we're talking about mature stories, we immediately throw out all of the children's slices, but they're likely the largest piece. Then we throw out Asia late-night, because their otaku are really similar to Japan's and spend huge dollars relative to North Americans. Then we're left with the anglosphere and the non-English European late-night slices.
So now I'll get into what exactly merchandising means in the late-night anime sense, because I get the feeling that a lot of us here have assumed merchandising to mean toys or physical goods. Kraavdran actually pointed out that there's a music but, I think, erroneously attributed the wrong part of the graph to it (it's the tiny yellow slice between the dark yellow bar and the pink bar). But, the role music plays hints at how late-night anime is funded and why Japanese and Asian otaku will always outspend everyone else.
For the purposes of this exercise, let's suppose that we want to produce a hot new anime. As Nate pointed out, we have to pay for late-night TV slots, but simply airing on TV is obviously not our goal here. First, we need someone to fund our anime. These will typically be media conglomerates: record labels, production agencies, publishers, etc. And so we get a few of these corporate partners together to form our production committee. Cool. Now these production committee members are going to use the anime as a vehicle to push various things. This is where the idea of merchandising as the biggest slice comes in. In children's anime, this is stuff like toys and idk pens and pencils and folders and all sorts of stuff gets pushed.
Late night anime also has all of that stuff, but there's more to it. Are you adapting a light novel or manga? Then the publisher of that manga or light novel is on the committee and is going to want to make sure the anime results in increased sales of the original work and they're gonna want exclusive character spreads for Newtype or Pash or whatever anime magazine they're publishing. Why is there a record label on the production committee? Because they're going to be lining up one of their artists to perform the OP and ED singles and they're gonna wanna sell a ton of those (Have you ever wondered why the big Aniplex shows always feature the same artists? Now you know: it's because Aniplex is owned by Sony and Sony uses anime to push their new talent). How do we cast characters? Oh, we'll go with an associated agency because there's an up and coming seiyuu that we might want to push.
And so the name of the game for late-night shows is this mixed-media push that you can never replicate in North America. A really good example of this is The iDOLM@STER, which began life as an arcade game and exploded in popularity. And iM@S makes bank for Namco because not only are they able to sell the home version of the video game, but since the game is about idols, they can sell a ton of CDs. And now that they've sold a ton of CDs, they can put on huge concerts. And so it finally gets an anime; how do you get people to buy it? Include limited edition CDs with it! Wait, the concerts are getting too popular, what do you do? Start a lottery, where you can get a chance to order a ticket for every CD you buy!
There's a lot more stuff like this. You bundle an OVA episode with a volume of the manga to jumpstart some sales. You include codes for rare items for your mobile game in the upcoming associated CD single. You include tickets for seiyuu events in your anime BD releases. And while I used an idol anime as an example, it's not the only case like this. Most late-night anime use these things to varying degrees and if they don't, they're probably the ones that don't sell that well (which is not a judgement of their quality; see: Yuasa anime).
And like I said before, it's not just Japan. HK/SG/KR/TW otaku all share the same habits, likely a result of the relative ease of importing in those locations. The record labels in Japan do anison concerts in those places regularly and flights to Japan from those places are cheap enough that flying over for an event or concert is feasible for a lot of people. I know of a few people in North America who do a yearly trip to Japan for things like that too. But on top of that, CDs cost twice as much in Japan as they do in North America and BD volumes cost something six times more when you take an entire show into account. In the face of all of this, there's simply no way the North American market is able to generate, proportionally, anywhere near the amount of money to have any influence.