It is no secret that Nintendo has been big on cutting video game costs, which isn't a bad idea, the only thing I find weird is that they sell 4 million+ copies very easily yet still cut costs anyway (because fuck it).
As for Marza planet helping, SEGA outsources a lot of stuff too, especially in their prime. I won't fault them on that. I do question the content on disc, like Splatoon, Mario Kart 8 and even Smash had less content than prior entries (Splatoon had no prior entries, i know).