The incentive will be to hype the game up, encourage people to preorder, go on a massive marketing spend, and then don't fix anything broken about it after launch to make sure it's dead within 2 years in time for the new hype cycle.

If your game only has 10 hours of gameplay, people will complain that it's too short. Then your game gets bad reviews and you don't eat.

So you need to have more gameplay, and that's either through cleverly addictive game mechanics or a ton of expensive to produce content.

Plenty of games have less than 10h of gameplay, and an even bigger amount of games have less than 10h of non grind gameplay. Portal is a good example

That's only if you didn't tell the players your game has 10 hours of gameplay, and made them expect it to have much more. I.e. you engaged in dishonest marketing.

If you present the game honestly, then people can evaluate the price you're asking for vs. what's being offered, and they have no reason to complain that it was too short.

It depends on the game and on how it's advertised. And I personally prefer 10 fun hours than 25 padded to hell and back. Other than Portal, there's also the latest Wolfenstein game, which had less than 10 hours of gameplay.