everytime you put money into the pot your gambling. but if your a good player, you would do it mostly when the odds are in your favour. it could be refered to as educated gambling. certain aspects of the game though make the game more skill based than a pure gambling game.
you have a tourney it seats 100 people and everyone is equally as good as each other. there are blinds but they never raise up through the levels. now because everyone is equally skilled at playing poker and everybody gets the same luck the players who will excel are the players who get the good luck first. now they will get ahead to start with, but sooner or later they may hit there bad luck and so loose chips. this happens to all the players and everyone would stay about even and the game might take forever! however, if you manage to double up through a bit of good fortune and your equally as good as every other player. and then you think of your extra chips as an advantage then there is something you can do to use this advantage and is as follows-

they are extra chips you can use to play hands you wouldn't normally work with. this increases your chances of winning the tourney. - the reasons as follows;
advantage management.
by spending your extra chips wisely you are able to improve the amount of chips you win due to the fact that you will see more flops and so win more hands, than a person who doesn't do this. - but its not that simple, this method wouldn't work for my example tourney above. Because Mike Caro says as one of his theories of poker that one player could play twice as many hands as another player and both would still end up approx even stacked. So how could this be an advantage? well that is due to the added factor of things such as the bluff and more importantly the read.
the bluff.
now lets take our tourney from before and add a new player into it. this player is just as skilled as every other play except he can bluff 10% better than the rest! now tell me who do you think will win? he has an advantage that cannot be put down to luck because it is his own ability or skill that is his winning formula! Once he is sat on a few chips he can loosen up the hands he is floping with and so play more hands and so have a larger opertunity to make well timed reads and bluffs. I mention reads because it is a skill i personally believe to be one of the most important tools in poker. the most sucessful bluffs come from good reads of play. So bluffing is a skill and is not determined by odds.
other factors which put skill into poker are listed below.

-ability to play a winning form of poker (dependant on players ability) *
knowing your odds and likelyhoods (dependant on players ability) *
-reading plays. the better you are at this, the more well timed bluffs, calls and folds you will make ahead of the lesser experienced player and so reducing the luck you would otherwise need to rely on.
* what i mean about players abililty is that because not everyone is equally as good at poker this gives the pros the advantage over the beginers and so eliminates the gambling aspect for the better player.

these are just a few ideas but answer my following question.

If you were to push your stack all-in everytime you had the odds in your favour how long would it take you to win the wsop?

based on the idea that poker is a game of gambling you'de never win!

so why have pros like doyle brunson, phil ivey, phil hellmuth dan harington etc been so consistant?

because their poker playing abilities are overall better than everyone elses!