The 5k miles OCI is just a common mid ground. Some people with certain driving condition and engine may need 3k miles OCI or less. I do not believe that using boutique oil will benefit much. PAO is better than typical group III but it is not 2x better, more like < 5% better for daily driving cars.
Some engines are burning oil from 0miles, it is just designed that way, unfortunately, and industry standard is pretty linient with 1L/1200 miles limit of oil consumption.
If our car burns oil, getting low SAPS oil maybe beneficial and extend the catalytic converter life longer that way. If our car does not burn oil, we do not really worry if we use mid or high SAPS oil.
Standardized test that makes an oil get API SP or Dexos 1 gen3, or VW 508/509 approval is a good base line. They are all about the same regardless brands, base oil, or price. I believe in number, science, standardized tests, not speculation and marketing.