To be fair, Ultraman is the superior product.
You can argue that as much as you'd like...but it is.
Look at a show like Ultraman Nexus, or Tiga, or Dyna, or Gaia, or ANY recently made Ultra series (...maybe not Cosmos...) and you see...well, something that's much less merch driven, far more story driven.
It's like if the Kuuga era of Kamen Rider never actually ended and only changed the flavor of the story being told from year to year.
Of course this means that Ultraman is less profitable, and it doesn't help that the company behind it is as freelance as it is, instead of being a major corp like Toei.