I thought that too but look at all the maze clones back then from a licensed Alien game to KC Munchkin (it was Atari that went after the publisher, not Namco, due to similarities) and many more.

At this point, I don't think Namco cared about the home market, they were squarely focused on the arcade market, seemingly happy to collect licensing fees for home ports. They got really into the home market with the NES's popularity though.