This doesn't address the same points as Kilmer but yes, soot does get created due the nature of the DI process. This videos talks about soot elongating a timing chain.
What appears in this thread is drivel driven by the person delivering the message moreso than listening to the merits of Kilmer's statements themselves.
The general trend has been to chase fuel efficiency to meet standards AND increase obsolescence. The way Toyota used to do it was simply designing the engine to run leaner and leaner until the cat fails at about 220-300k. Toss in a failed valve cover gasket, and that sets the stage for a failed crankshaft or camshaft position sensor and getting stranded. Now, Toyota just happens to be the "nicest" of the companies in terms of causing troubles to the driveline of the vehicle. Other companies can fail and require repairs of parts essential to function like water pumps. Toyota wants to sell their hybrids now and others EVs.
No one really wants to tell people to monitor their long term fuel trim with some OBD tool because that would inform the customer of a "non-clinical" failure that would extend the life of the vehicle. Chances are, at 100k, the factory fuel mixture already can't be met, and you'll notice it when to disconnect the battery and then reconnect it, only to find the idling of the car is not right for a few starts until the computer "learns".
My mom has a Matrix. Yes, it still runs off the original injectors but I'm going to swap them out for new ones because it's taking too many rotations of the starter to get that thing to catch, and it no longer "instantaneously starts" after the engine is immediately shut off when it did so in the past.