In all of your examples except the last one, the mother can express after the birth, and will be able to do so much more easily with post-birth hormones.
But my point stands. An "insurance policy", like car insurance, weighs costs and benefits. Would you pay annual car insurance that costs far more than buying a new car?
The list of eventualities you've listed are unlikely, and the last one very unlikely in a mum with no previous indication. Even so, formula can tide the baby over until the mum is well enough to breastfeed.
So again, we are suggesting a mother should spend hours toiling away at something, getting anxious and frustrated, possibly with no benefit at all, certainly with no more than a negligible benefit to the baby.
I am a huge advocate of "ordinary" breastfeeding and also combi feeding. Breastfeeding is not only beneficial to the baby, but has health and convenience benefits to the mother if/when she gets the hang of it.
Colostrum harvesting has a much much worse benefit to cost ratio.