The difference for me is that when I play a single table sit & go I'm striving for a 1st place win, which is realistic within an hour. You can get there with skill and discipline.
With MTTs, especially the big ones (thousands of entries), 1st place is a completely irrational goal (for me). It takes a number of hours to just place in these MTTs. To get to that point you need skill, discipline, patience
AND luck.
Yes, you
NEED luck to make it to the final table of a big MTT. You need your Aces to hold up. You also need some of your lower pair hands (e.g. 99 or 55) to beat the other guy's Aces. You need your
flush not to be beat by an
with a fourth club on the river.