This is one concept that I haven't really been able to grasp. Harrington often says that when you are pot-committed and won't be able to fold on the river, you need to just push in on the turn.

Will Tipton in his books said something similar explaining it by basically saying it denies your opponent options, I think.

But I don't really get it. For example, if you believe you are favored, or getting too good odds and therefore have to stay in, wouldn't just playing passively to encourage opponent's losing hands to put more money in be an option?

Does the concept only apply when there are possible draws?

You don't know what your opponent has. Checking and calling more or less puts you in bluff catching mode. By shoving, you add fold equity to your EV calculation. It could depend on the context of course.

I think it is outdated. Sure the more draw heavy the board is the more you need to commit to either end the hand or force someone to call due to pot odds with a draw but you allow your opponent to get away from his bluffs. However on dry boards with a top pair that is not vulnerable to rivers shoving probably only allows your opponent to call with better and fold worse.

Pretty much this, unless you are completely nutted and trying to trap, shoving is almost always the best option under the circumstances you mentioned.

There are good odds that if villain is on a draw and you are already pot committed, your shove will still be called

If villain isn't on a draw but has you beat, you still have FE (ex villain has TPGK or JJ on AXX board (he will probably call one street, but not two), etc)

Look at it this way, theres two ways to win in Holdem
1) Show down and having the best hand
2) Getting villians to fold.

Check calling will guarantee you a chance to win by option 1, but shoving will give you a chance at option 2 and if you get called you still can win by option 1


Also, what do you consider to be "pot committed"?

True pot commitment (where both players have to go broke on the river no matter what) rarely happens, and it's usually because the turn was played weirdly by one or both players (with a very small bet). There are plenty of spots where you can call (or make) a small bet on the turn (especially with a draw) and then fold when you miss. It's never pleasant when you have 2/3 of your stack in the middle and you have to fold with no showdown, but there's no law that says you have to go all in on the turn or river when the pot gets big.

Generally speaking, however, being able to get all in as a shover ("getting the last bet in") is beneficial, since it gives you an additional way to win, and prevents you being bluffed off your equity.