Because it does the job I need in my engines, and cost is much less. It like comparing a cup of Maxwell house coffee to Starbucks coofee. I don't need to spend $5.00 for a cup of coffee.
Are you doing engine oil analysis? Have you done actual back to back testing on an engine dyno between the cheap oil you use and a quality synthetic oil (it is very expensive to correctly test engine oils…so much so that most people won’t do it)?
When you do some comprehensive testing you quickly learn quality oil is cheap and cheap oil is just cheap.
