like half of their 70s output was just "Scooby Doo but with a car/shark/caveman/two dogs/ghost/a different ghost/very small man/whatever a Shmoo is"
That they were, lol. Shit, Josie and the Pussycats was basically the original pitch of Scooby-Doo (before they gave up on the idea of Daphne, Velma, Fred, and Shaggy being a band) dug out and adapted for Archie Comics.
I'll give Hanna-Barbera this, though: they plagiarised from the best, and they
understood what they were plagiarising. (I doubt any other studio handed
Fish Police would've made Angel Jones the best character in it, but H-B managed, lol.) Even if that meant that once they found a formula, they'd recycle it to death, lol.