Eh, I think that was true in the late 90's and early 00's when Pokemon was trying to carve out a niche but I don't think the target audience of the franchise is largely based around that age anymore. As it has expanded to include gen Z in their early 20's as well as millennials that grew up with it being popular at the time they were kids. With the release of Pokemon Go and the Pokemon Let's Go series and even Arceus, it shows they definitely do target an older audience that might have not kept up with the franchise but are familiar with the brand. I'm pretty sure that's why they milk the Kanto and Johto regions so much. Even if you weren't a fan of Pokemon as a kid those mons are more recognized by the older crowd.
You also have to separate the mag's target audience from the developer's target audience. I'm sure Corocoro is targeted to younger readers.
No it's still very much the same now despite older fans clinging to the hope that it's no longer the case, the primary target always will be the younger audience they are the reason it's the biggest franchise older fans just think the is a shift to them when in actual fact the franchise is just adjusting to a more modern younger audience.
Nothing about LG or Arceus says older audience, LG is the for more casual audience while Arceus is a different take on the formula it no more targets older audience than 3d Mario does over 2d.