Helps that it was so short, the writers didn't need to try and remain "fresh" or even have people go stale (like many people generally do) on them. Plus they didn't have to react to anything either, just write the show, shoot the episodes and never go back.
Imagine being a successful artist and having to deal with fans who either whinge cause you don't progress OR whinge because you do progress?
My favourite type of fans are the ones who like what you did and then 10 years later no longer like what you did because it is uncool to still like that thing from that time. I get you may not like the thing that the thing you liked turned into now but shitting on what you used to like seems very odd to me.
I can honestly say there is not one thing that i used to like (and i like so much what is considered embarrassing) that i still don't go back to now and enjoy just as much as i did as a kid, teenager, 20's or 30's. When i watch Astro Boy, Power Rangers, Ninja Turtles or anything else like that i still enjoy it.
I think a lot of people take life too seriously........it seems a very human thing to shit on something that they once liked.