I completely agree with that . I myself have put a lot of effort on the first weeks, and after that I just thought "Oh still 3 months to go .. still got plenty of time", and then suddenly lost interest. And I think that's what happened with a lot of entrants .
I was originally all for it, as I was working 25 hours a week at the time and needed something to pass the time with. But then my workload rose exponentially, and I ran out of time to do anything. By the time T minus 1 week came about, Tiny Defense Gunner (Defendrex) had no gameplay, only techdemo, and even my backup plan of Tiny Pacman was too complex to bring about in the time I had left.
A shorter timeline would have focused me to make a small design that would definitely work, instead of taking my time finding out that my incomplete design would not work. But hey; "I have not failed. I have discovered a thousand ways that don't work."