Med students are excellent at picking out the better specialties. They aren't perfect at it but overall the STEP score correlates with the specialty. Prestige, Lifestyle and Money are the major factors. If there are a lot of midlevels in the "field" then the prestige factor is lower so that leaves lifestyle and money.
I'd rather earn $500k as a Physician who is at the top of the food chain than $500K being at the bottom. If you aren't at the table then you are on the menu. Anesthesiology is viewed as low prestige and a non money maker. CMS views it as a nursing level duty based on reimbursement levels.
Eventually, Medicare for all or a Medicare Option will pass. Those specialties that can weather that storm will be at the top of the food chain. Anesthesiology and EM will be lucky to survive "Medicare for all" vs Ortho which gets paid 80% of a typical HMO rate.
Deciding upon a specialty is a huge choice almost as big as deciding who to marry. In some ways it may be a bigger decision because most rarely get a second bite at the apple with specialty choice post residency.