I do not think Toyota & Lexus owners always use these products (factory original 50/50 mixture of Toyota Long Life Antifreeze and distilled water). I do agree that Toyota & Lexus do go for a long long time but look at their service book. They want you in like once per month! The coolant in my booklet says to “flush and change coolant” every 15K miles per my manual and (3) Lexus dealers I talk to about this and a timing belt. All three recommended flushing as do many manufacture of cars/trucks/bikes I every looked in my wife’s ML-420, my gsxr1100 motorcycle, and even my tractor & all these state drain flush and fill.
Also your coolant will break down overtime and cause buildups. It is a proven fact. It that were not true, you would not have coolant filters on many trucks/tractors etc.
As you could be correct but I think I will use continue using Diesel coolants since they are tried & true long below 1987. I have friends that trust this stuff from there small tractors up to the New PeterBilt rigs (over $200K.).
Lastly, Toyota might be zero and diesel could be low but, you nor I, don’t know what low means (ie in terms of percent.) I do not shop at NAPA, Pep boys etc so I do not know the validly of this statement. It could be true. Also many autopart stores will not carry hybrid coolants because the average “joe” does not care that much about his anti-freeze and the price will be do high. They all go to Wal-mart and buy Prestone (yellow) for $4.99 and think that it is fine.
At least you care about the car to look up the info and debate on it. That is great. Many people do not care or go to the dealer for everything and it cost more then the car.