So I've not abandoned the list... but it seems more like a lifelong goal to keep up with the movers and shakers of the list. I mean right now "Let the Right One In" (2008) is not on the list, but was when I started this. To be fair I'd already seen that when it first came out but I was going to revisit it solely for the purpose of it crept up on the list.
Now its off the List I've put my plans to revisit it to the back of my mind, even though its a fantastic movie.
Another case in point, "Perks of Being a Wallflower" has disappeared and been replaced by "Arsenic and Old Lace". This happens all the time, but luckily I found sites which notes these changes.
IMDb Top 250 Informer
IMDb Top 250 History
(I'm preferring the latter as it has a more similar layout to that of the IMBd site and you can see clearly what new movies are in, and a nice feature of what past movies have been in the list for one day, but the Informer site lets you track what you've seen on that site if you register, so either or both is good. Though you can check-in to what you watch on IMDb itself so there's that...)
Where before I was trying to watch all movies, including those I'd seen before, now I'm concentrating on those I never have. (And not just those from the IMDb Top 250, just movies I've generally never seen... re- my last "List of Shame" post)
So in closing, no I've not given up, I've just changed the rules on myself.