Why isn’t colostrum enough???

I constantly see mothers stressing about “milk not coming in right away”. What is with the expectation that you will have milk as soon as you have a baby? Why don’t people think tiny frequent amounts of colostrum for the few days isn’t enough?

Who is telling these women they need to supplement in the early days? (Which then decreases how much your baby is in the boob and encourages the delay)

I’m a this maybe just an American thing?

Edit: I don’t meant shame women that need to supplement. It’s more of wondering if there is an unrealistic expectation that we should be immediately flowing with milk baby should be content and not cry or feed frequently. This is question for moms saying “I had to supplement because my milk took 3 days to come in” (which is normal) I worry women are feeling inadequate due to poor information. (Don’t get me started on TikTok oversuppliers making women who “only” pump 2-3oz inadequate…which is a normal amount!)

Edit: I’m adding that there are definitely circumstances when supplementation is needed (poor latch/milk transfer, low blood sugar, severe jaundice, dry diapers, premature babies, etc.) My post was more directed at mothers thinking you need to supplement without these issues. Newborn babies are hungry all the time and are constantly waking up to feed frequently and aren’t supposed to sleep well. This is how they keep their tiny bellies full with the 10-30mls of colostrum that is produced. And this is how you body gets the signal to make milk. Being ridiculously engorged and in pain on day 4-5 is NORMAL, this is expected to happen while your supply comes is and takes a long time to regulate. A hungry baby isn’t a sign of poor supply (unless there are actual physical indications they are under fed as mentioned earlier in my edit).