Like many controversial issues regarding government policy, it's an arbitrary line. Different people's brains are susceptible to addiction to different things. I don't enjoy drinking but I still understand some people struggle with alcohol addiction and that it could potentially be a net positive if alcohol were outright banned. It's pretty condescending to simplify people struggling with addiction as simply lacking self control.
The work performed by doctors is not much more difficult than that of a mechanic or some trade skill. The difference in pay, at least in the US, is due to the artificial barriers of entry such as requiring 12 years of education, 4 years of which (undergrad) is almost entirely irrelevant to the actual skill of practicing medicine.
In addition to this constraint on supply, the demand is inflated by medical insurance which makes consumers price insensitive and produces a "use it or lose it" mentality where people are compelled get certain services they don't really need to not let the unused budget expire.
The solution is to increase supply by making medical education a 4 year program that has no undergrad prerequisite and no residency postrequisite like it is in many parts of the world and also reducing the unnecessary demand by removing any government requirement that employers provide medical insurance or any subsidy towards getting medical insurance.
The problem with raises and promotions is that it's slow, requires a lot more work from the manager, and doesn't increase the manager's number of reports. Thus hiring externally is a lot easier and more beneficial to the manager. Especially for those managers who are serial job hoppers themselves.
Another factor is the recruiting teams are assessed on conversion, how many passed phone screens, on sites, and offer accepts etc, but not on the performance of those employees after they join. So recruiters just spam anyone they think will have a remote chance of passing some stage of the interview process.
There have to be consequences to hiring a bad hire for the recruiting team and they have to be severe enough to make recruiting risk averse.
But this will never be the case if the organization is in growth mode where everything manager is trying to get as much headcount and hiring as fast as possible.
In my experience short term and long term memory recall speed and accuracy are strongly correlated. It's unlikely someone will be able to swiftly traverse a large long term memory graph, in a manner that would allow you to derive deep insights not just recalling a single piece of information, but have a poor short term memory.
However I do believe long term memory is more robust so if you're in a mentally compromised state, such as having a headache, it will be less affected. So if you have to work through a hard problem on a deadline but have a headache, you can rely on heuristics stored in long term memory rather than deriving everything in short term memory.