That practically was the case before in the mid to late 20th century that even as Japan began improving in the 50s, many Western animation production houses still turned to it because it provided cheap, quick animation. Historically, anything made in Japan had the same reputation as anything made in China today (though that too is changing quickly for the latter). Comes to think of it in hindsight, there’s a reason why in the 20th century before there were a lot of Japanese co-productions.
These included Alfred J Kwak, Superbook, GI Joe, Batman, Gargoyles and Thundercats. Currently, this has shifted to Korea and China especially for both Japanese and American productions. (I guess Japan at this point’s now a truly developed country so for most of the part, there needn’t much Japanese co-productions since it’s now a bit too expensive for that.) Not that there aren’t any more Japanese and Western co-productions but that these have gotten rarer.
Looking back, there was a time when Japan was more or less in the same economic situation as China is today. In the sense of being rising but still fairly cheap enough for international companies to turn to when producing productions on the cheap.