As the blinds get higher in a tournament - an all-in bet becomes more and more popular because the blinds and antes are worth so much.
If the blinds were constantly 10/20 or so for the duration of the event, the majority of people would be knocked out later in the event, and the event would be a lot more about outplaying eachother post flop than shoving preflop.
A shove preflop when your M is low (or everybody's M is low) is a direct attempt to get everybody to fold, to pick up the blinds or antes - USSUALLY - since this becomes standard, when you actually have a hand, you shove for everything and hope your shove gets disguises as weekness.
Generally at these stages it's shove or fold for just about everybody at the table, as they're having trouble keeping up with the blinds.
Your original question is flawed - what is the blind structure of the tournament? What are my reads on players who are all-in? What are the stack sizes? What are the blinds and antes at this moment in time? How close to a new tier of money?
Given the choice between staying uninvolved in a hand and keeping my tournament life off the line with a hand like say . . . KK - or potentially moving up to become the table's chip leader if I can dodge everybody hitting a set/2 pr/str8/flush/A, I have to weigh far too many factors than just "Okay, six people are all-in ahead of me (by the way I would call with that many people all-in, not only are your pot odds
ridiculous but you can expect hands like AK and AQ to have all their aces eaten up - unless of course I thought all the people being knocked out in the hand would move me up AND/OR I'm beaten and drawing dead with my outs to a set held in other players' hands -), that's two more than I'm allowed to call at this stage in the tournament."
You seem to be looking for a clear cut answer - to which there is none. The answer to most questions is "It depends." - and even with all the information on a given hand two players may play the same cards differently and get the same outcome.