It's important to remember that in 1961, Hanna-Barbera was probably the most respected animation company in America, not in spite of the limited animation process, but because of it. Hedda Hopper did a column on Hanna-Barbera in 1960 where she said that they had saved cartoons with their "streamlined" process:
It looked as if the cartoon industry was washed up and Hanna and Barbera with it. But as things turned out, that kick in the pants [getting kicked out of MGM] was a major piece of luck; they got up from a prone position and developed a new streamlined method of animation...
People who'd operated by the old slow method for 20 years switched to the quick way like a bunch of kids. "Our story men, Warren Foster and Mike Maltese, are all of 50 and they're fabulous. No one ages in our business and these men have been in cartooning since they were kids. Mike came to us from Warners, has a delicious sense of humor. He used to do eight theatrical cartoons a year, but wrote 78 stories for us in nine months -- the entire McGraw series.
Everybody knew that for animation to survive, it would have to shift its center of operations from movie theatres to TV, and H-B had figured out how to do that. Furthermore, they'd done it while maintaining a standard of voice acting, design and writing that was at least comparable to theatrical animation. The fact that they'd compromised the quality of animation was not all that important, partly because it was inevitable (animation had to adapt to TV budgets/schedules, or die), and partly because the importance of animation had been downplayed for years before H-B started their operation. The acclaim of H-B in the early '60s was the natural successor to the acclaim that UPA got in the '50s; UPA was trying to make art and H-B was trying to get sponsors, but both companies were emphasizing other things besides animation.
Of course, just as UPA's peak didn't last very long, Hanna-Barbera didn't maintain this level of respect for more than a few years. By the mid-'60s, it was becoming more apparent that their cartoons were getting worse, not better, and then with the boom in superhero and mystery cartoons, the old cartoon pros (like Maltese and Foster) were thrown overboard and the feeling of gratitude to H-B -- for keeping them employed -- turned to a sense of bitterness.