Yes, I read your comment clearly. You are still stuck with thick oils because you are so much worried about shearing or oil becoming thin at high temperatures, which was the problem with mineral oils, not synthetics. Even synthetics based on Group III.
With your logic, all new vehicles should have been destroyed within 2 or 3 years. Have some trust on science, and chemists working for manufacturers. This isn't our headache. We should just choose based on owner's manual and our driving style.
Short trips definitely benefit from 0W oils even in high heat areas, but not much benefit if you do frequently drive on long. In that case, 5W is ok to choose. Motorsports applications, or if you use the vehicle for towing, etc. should use group iv synthetic.
In 1998 Mobil 1 sued Castrol on marketing conventional oil as synthetic, but Castrol won the lawsuit. Why? Because they were able to prove in court that their oil can bear high temperatures without getting too thin. They were able to modify group iii oil in lab to create strength closer to group iv for regular use. Later, the definition of synthetic became loose, and group iii synthetics appeared in market. This is why engine oil from a reputable brand is very important, so we can trust the manufacturer on its engineering.
