I wager that most people hardly ever try the recipes they see, and of those that do, most suck at cooking. The point at which you start fast forwarding through stuff is the point in which you don't need cooking videos anymore and can just work off a written recipe. People want entertainment, and cooking is one of those easily monetized. non-politicized things on youtube that's just ripe to turn your brain off and follow along.
You don't need to show the initial 5 minutes of stirring which are unambiguously not golden brown, you do need to show the "it looks brownish but it's not yet golden brown" and the "this is done" steps - and if you cut out the unimportant parts which aren't relevant to any decision, then it helps focus the learner's attention where it's pedagogically most effective.
In an ideal world they would also show "this is how it looks when it's too much and you should have stopped earlier", but that requires cooking/wasting an extra batch.
And for onion cutting, instead of spending the valuable viewer's time on looking at how you cut 5 onions, instead show how you cut 1 onion but make sure that the camera angles make it clearly visible how exactly you do it while you explain it; then the other 4 onions then add no value and can be cut off-camera.