There is a minor genre of YouTube content with people speed-running longer games (e.g. Fallout, Skyrim) to fit into the two hour Steam-return window.

Ironically because speed-running requires a lot of practice this often means purchasing two copies of the game - the first to practice with, and the second to be (potentially) refunded!

The problem I've now noticed is that there are many games with ~2hrs of filler before real content (which may only be worth 1-2hrs) begins...

eh, it’s not the end of the world if games just have to provide more than 2 hours gameplay. Steam is targeted at longer form entertainment. Just extend the story out with some puzzles or challenges that send the gameplay over 2 hours.

As another poster mentioned, some have done just that - added "filler" to a game to inflate it over the 2 hour bar, which is disappointing.

There should be some sliding scale where you can make a great 2 hour or less game without the risk of infinite refunding (perhaps the game could be marked with a "half-way" point, etc, though that would involve the shop actually playing it).

I know this happened a lot with Sonic Forces.