One of my biggest learnings is that no matter what I do it takes quite a while to cook a meal. Huge complex meals can take hours to prepare, but even a simple meal usually takes me half an hour - because that's just the time it takes to grab the ingredients, boil water for pasta/rice/potatoes/..., cook and present it. The time it takes to cook a meal is largely determined by the duration of the longest step. All the rest is done in parallel, with more complex recipes simply requiring more multitasking. So cooking a simpler meal often makes for a less stressful experience and simpler flavours, but often doesn't save much time.
Also I found that slow cooking brings out the best flavours and aroma.
1. To chop an onion or a shallot real fast, you need to do it a lot. In restaurant, you can probably chop 100x what you can do at home. Grated carrot with julienne knive ? It seems absurd to me at the time, but in the end that's a training.
2. To not lose time, you need the proper tools (and know how to use them). Sharped knive, flour stifler, ... . For example, my knives are not sharpened often enough, which means I cannot chop vegetables that well.
3. Cooking several things in parrallel will go wrong if you do not know what to look at before things get burned. If you are too "prudent", you will lower the fires and degrade your scalability.
This is not a mystery. People don't "cook along" with videos. People watch cooking videos for either to get inspired or for a vibe, most often for both.
A stew might take hours to be ready, but the core idea of it can be expressed succinctly in a few sentences. Totally made up example: "We brown beef, and then simmer it with potatoes low and slow with the bones in. It is ready when the meat falls off from the bones. Spice with a pinch of cinnamon." Those are long and sweaty hours in a kitchen to make it, but you can read the idea in seconds. Put the details and quantities in the description. Those few who want to cook it will find it there.
If there is some technique or twist, make a video about that specifically? It doesn't all have to be recipes. I have watched a video the other day where a person explained why they put a few drops of water in the pan when they are frying bacon. If they would have done it in the middle of a 20 minute video I might have missed it. Or what is even more likely would have been skeptical of the technique without the added explanation and test pieces where he has done it both ways to show the difference.
And videos you watch for vibes are not about cooking. They are about the personality of the presenter, that parasocial interaction. It doesn't matter how the food tastes. You won't eat it anyway. What matters are the feelings you experience while watching it.
But a lot of recipes require you to multitask between several parallel workflows of ingredient preparation and combination, keeping you active in cooking until either the final step ("put everything except the garnish into the oven for X minutes") or until the recipe is complete.
Audiences don't want long segments of monotonic action with predictable outcome. No need to show how to slice a kilo of onions. It doesn't sound like the chef videos you mentioned suffer from this, but your "want fast" generalization is off the mark.
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.
Either way. He's got the consistently longest cooking videos on youtube. He explains that long videos don't do well. But it takes time to cook. Sometimes a long time. And he's a professional chef. So he goes very fast. All in order to make videos shorter so the audience doesn't turn away. Even with prep time where everything is arranged before filming, it will take him something like 20-30 minutes to finish one recipe. But his cooking is consistent, you watch him caramelize onions, you watch him multitask. Once again, he's very fast, but still, it's just not that fast to cook.
Audiences want fast. "quick 10 minute recipes" are all the fad. Equivalent to bite size twitter feeds and tik tok videos even though cooking can take a long time. But that's what the audience wants, and that's what the audience gets.