Scooby Doo was never a good show.
Everyone who grew up watching it did so because it was the only thing available. Back ground noise while you played with your toys or read a magazine. A Pup Name Scooby Doo was actually entertaining and after that it they tried very hard to make Scooby Doo cartoons palatable to viewers of a modern era. No more shitty 70s cartoon flat comedy.
Then Mystery Inc rose the bar so high that they had no other choice but to emulate other cartoons and make Scooby Doo slap stick.