The problem isn’t marketing, it’s the manufacturers constantly trying to game emissions and fuel economy legislation by tweaking everything from the oil to the freaking scent of the Christmas tree air freshener hanging from the mirror.
This week it’s Dexos, next week it’s Flexos, then it’ll be Hexos in the 2022 models, blah, blah, all because someone thinks tweaking the oil will give a .0002 percent mileage increase. That’s why all the OEMs are going toward this urine-water thin oil, because thin oil increases mileage. Do they care about your engine’s lifespan? Hell no.
The thing that matters the most with oil is to use the right oil for the operating conditions and to change it regularly.
Also, the WORST thing for an engine is not using the wrong oil. It’s not using the engine! Lack of use and poor storage practices kill engines far faster than any “wrong” choice of oil ever would.