That Link's Awakening HD fan game lasted for, like, a week, and that was barely anything beyond a direct copy. Could be there's nothing for the lawyers to litigate, or it could be they're building a broader case based on a cohesive body of evidence.
All that to say, don't mistake inaction for inability to act.
Not only that, but it is not like any of the Pokemon games. Some of the character models are certainly uncanny, and other than pal spheres instead of pokeballs, the two games aren't even similar.
Nintendo is the most litigation heavy company in the world if they've not been taken down already then it's obviously because there is no case. The game has been in development for like 2 years now and Nintendo has had plenty of time. It's come out now, which means it's not a problem.
Right when SE takes down Jokémon for being a ripoff of Dragon Quest, a game that released ten years before it... I'll take derivative fun over derivative garbage released year after year with zero innovation or progression in quality of gameplay.
Was it an assault rifle? Or was it glitching building stairs in a place where you get infinite XP? Either way that video is what inspired this meme (for me at least)