I think you are onto something. I to find smaller sizes appear to work better then the full size product. Most of my cosmetics are Lancôme. Found a product at target called JULEP it’s a daily moisturizer. Looking at the ingredients from both the high priced moisturizer and the Julep brand, they were the same. For the past 8 weeks I’m using julep, and so far so good.
A lot of your high price make up comes in fancy boxes and bottles, so we pay for that.