I think this is a good point.The immediacy of the task at hand is important to me. Remember, we're talking about a situation where the GM has a prepped adventure ready. If that's the case, why dilly dally? Jump to the beginning of the actual adventure. Put the characters in some kind of situation that demands action.
Everyone comes over to play the game, quite often an action/adventure game. The idea that the players just want to sit around and do the random sandbox free form role play just does not fit.
I've had players complain they want to do random sandbox free form role play more before the game. As DM I say no, but "the game starts at 6pm, so if you all want to come over and role play among yourselves, you can". Amazingly no player wants to come over "early" just to sit around and do random sandbox free form role play. They only want to waste game time doing it...
This only sounds good on paper. The idea that the players must "feel good" and "care" about the adventure is often a non starter. The DM can do the "d20 pitch" and toss out 20 adventure ideas. The players will then drink some Mt. Dew and pick one. At random. At best they will pick the one that "sounds cool". But it is not like you can detail every tiny part of the adventure. It's like asking someone what new movie they want to watch. You can't describe the whole movie from start to finish and then say "ok, you want to watch that?"GM should not prepare adventures that the PCs do not care about and then expect players to play through them. And of course the players tend to be willing to go along in such situations, you just need to give them some somewhat adequately presented reasons and they are likely to be willing to be persuaded by some of them. It is like in improv acting, being willing to go with the flow, but there still needs to be some input from the GM the players can react to.
For my more advanced good players I like to do flashback 'mini games' over post or discord. It's a great way to fill in things for a character.It is established, in a sense that the player, as playing the character feels in some way about the situation they are in. If you later introduce additional emotional context, that feeling is likely to change. But as it is a flashback, then logically they should have felt that way from the get go. Like if I first played my character as having more callous and mercenary attitude about the quest, but then was really moved by the king's plight in the flashback scene (and the other characters were there to see it) then my feelings and behaviour in the beginning of the game were inconsistent with this.