From your perspective, they were doable.
I may have missed 6-7 collectibles total(!) throughout the entire course of the event. I am now still below 75 pumpkins. So, my perspective differs.
It was, based on the output of the Random Number Generator, technically impossible for some players, including me, to complete this "achievement".
They could have an achievement "Flip a coin. Get Heads. You only get 1 flip." - same logic as this "achievement".
Some players are screwed by the RNG, others benefit.
Tell me about fair, about "entitlement".
I have gotten well over 6000 pumpkins during the event. I even gave lots of them away to lower levelled players - who, unlike me, have had NO PROBLEM AT ALL to complete "Pumpking".
It feels completely idiotic to be cheated out of an "achievement" that I have put a whole lot of effort (and the occasional Fairy Fire) into when it's handed to others on a silver platter.
If we deserve anything, it's being treated equally.
And that doesn't mean "Hey, you're an extremely active high level player, how about we screw you over?"
My complaint is that this is not the first time this happened. I've been around since long before the "Crisis" quest where some players got their quest done with 1 adventure reward, others still had the shaft after 30, requiring an adventure which, at that time, was itself only available as a random reward from Adventure searches (at 3% chance, mind you).
The devs still have not learned that random rewards do badly for "achievements".
Years after we told them, strongly, and they replied that they got the memo. Seems that either their memory is bad - or their comprehension capability is low.
Aside from that: How can it be that some players consistently get 20+ collectibles, day after day, week after week, month after month --- while other players get only half that much? Not even worth mentioning, given all the glaring problems this game still has - 3 years after Beta ended.