First, there are plenty of jobs, but not enough people that have decided to develop themselves enough to have the skills to do them. For example (a real life one, unfortunately for me): I need a biopsy of a mass near my heart, but the current waiting time for this procedure here in Seattle (at both major hospitals) is two months. What we do have is plenty of regulations that constrain the supply of physicians, servic…
I think that medicine is a bad example of the point you are trying to make though... It has a lot of embedded costs and roadblocks that aren't really related to regulation.
For example - the procedure you describe is highly specialised, and can only be learnt in certain places. Say there are 4 people that can do this procedure at a hospital. Attracting a doctor who can do the procedure is often a complicated task. In a highly specialised field thay may need to be incentivised, which also costs money. It is very difficult to control where doctors work - they invariably want to work in large established centres, which are already saturated (and so they don't work full time, they end up taking small bits of work here and there). This problem isn't necessarily solved by training an order of magnitude more - increasing the true training capacity of the health system is actually very hard, and takes a long time. Pumping up the inflow of trainees at one end just means that competition increases, doctors spend more time optimising for selection onto programs and working in certain places rather than doing their training. They also develop a sense of entitlement due to the high debt and difficult and competitive training ie they feel like they should be able to work wherever they want to work, not where they are forced to go.
There is limited space in the endoscopy suites usually - increasing capacity means building a new suite, buying all the equipment, paying the nurses, rostering another anaesthetist. The added cost is easily more than a million dollars just to get started, without the doctor even doing any procedures. There could also be other bottlenecks like sufficient recovery areas and clerical staff. This high threshold means that an overloaded service will languish for long periods before capacity is increased.