No offense intended, but all of your suggestions sound very stereotypically Italian, which is to say they put an enormous emphasis on the traditional ways that pasta and sauces are made in various places in Italy. There's nothing wrong with this, celebrate tradition and heritage all you want, but that's very different to what Kenji goes for in general and what Serious Eats goes for in general. Their goal is usually to provide techniques that are then used in recipes to achieve a desired outcome.
Whether that outcome is considered traditional or correct by anyone is not something that is considered. The techniques are a tool to achieve an outcome, and how much or little you use those tools is left to the cook, rather than being dictated by tradition or custom.
Pasta water contains starch, which helps to thicken sauces. If you want a thick and glossy sauce, it is one way to do it. End of story. It is a technique to achieve a desirable goal, nothing more. Whether anyone traditionally in Italy does this or not is immaterial.
Similarly, fats are flavorful. Adding flavorful fat to increase flavor in a sauce is desirable. Whether anyone traditionally does this is immaterial if people think it tastes good.
I think you misunderstood what I was trying to contribute though, since I was not attempting to celebrate anything nor to emphasize on traditions. I was just saying those "goals" have well known solutions that differs for some good reasons with what is described in the article, which claims (by its title) to explain "the right way" on basis that are unclear to me.
I do not know "Serious Eats" nor the author, so I'm sorry if I am antagonizing (not my intent, but I get it might be seen this way) a celebrity or his fans and in this upsetting people. I'm just contributing things I know from experience, whereas arguments like "this is one way, end of story" seems brittle to me, because you are basically dismissing the points that I probably didn't even explain decently (on your examples: you add pasta water, you get starch in the sauce which helps thickening things but you dilute other ingredients and will need to cook for more time to have the liquids evaporate thereby overcooking the pasta; you add "fats" like butter or oil at the end and you change the flavour of the dish significantly, other than its nutritions). Then again, if that's what you are looking for, great, I think I said at the beginning there's no objectively right or wrong, it's food we are talking about, if you are happy with eating the outcome good for you.
I mean, by all means please try it, and with that I mean actually get in the kitchen and do it, I think you'll realise there's a lot more than just "using a technique that makes sense in theory, end of story" to get your goals.
Whether that outcome is considered traditional or correct by anyone is not something that is considered. The techniques are a tool to achieve an outcome, and how much or little you use those tools is left to the cook, rather than being dictated by tradition or custom.
Pasta water contains starch, which helps to thicken sauces. If you want a thick and glossy sauce, it is one way to do it. End of story. It is a technique to achieve a desirable goal, nothing more. Whether anyone traditionally in Italy does this or not is immaterial.
Similarly, fats are flavorful. Adding flavorful fat to increase flavor in a sauce is desirable. Whether anyone traditionally does this is immaterial if people think it tastes good.