I think people's perceptions of the importance of the DM is strongly colored by whether or not their groups feature multiple DM's. See, "vote with their feet" to me means that someone else is running the game because, well, we have, currently, three active DM's in our group and it used to be four. Trying to play the "players are a dime a dozen" card doesn't really work when all or at least most of your group is perfectly willing to take your place.
True. You have some people voting along those lines (where they are the only DM at their table) gravitating towards DM being
most important given rarity
. On the other hand I'm the primary DM for our group but there are 2 others, but I would still cast my vote towards
DM most important. I'm pretty sure I'm not the only one in this category.
I think generally within the scope of our hobby DM's/GM's tick the most boxes in the hosting, prepping, planning session dates, keeping momentum going, recruiting, refereeing, entertaining...etc That is not to say that many players don't also tick these boxes from time to time or even often.
Even as a player I defer to the DM/GM. He has a unique role at the table that is not shared by any player. Sure a player can also be DM/GM at another table or another campaign - and in that table or campaign I would vote him at the
most important.
Perhaps the real debate is what does
most important mean in that context. Speaking for myself, and I'm not nearly eloquent to describe it correctly or fully, like some others on this board, but by the DM/GM being the
most important it is the acknowledgement that he/she is the leader (spearheader) of the game being played. If not him/her, another will be nominated/found to take that position.
Typically a RPG game cannot be played without such position being filled, thus making it the most important.
EDIT: And just like a leader in any organisation MUCH of the success of the overall venture is directly related to THEIR efforts.