Every time a come across the topic of unemployment I wonder what the fundamental thing is that is broken in an economy with a high unemployment rate. I mean unemployed people mean unused workforce and it seems that there should be a strong desire to make use of unused workforce. So what is it?

Are the unemployed not needed? Because we reached a level of efficiency and automation so that we no longer need all the available workforce to satisfy all the demand, i.e. is it a work distribution problem? This seems not to be the case because there are not enough teachers, the infrastructure is in bad shape, there are heavily overworked people and so on.

Do they have the wrong profession, one where no additional workforce is required? Is it a latency effect, i.e. available workforce in one sector lacks behind needed workforce while it is the opposite in another sector? Are they obsoleted by cheaper labor abroad?

Is it some kind of local extremum or vicious cycle in which the economy got stuck, e.g. unemployed would consume stuff if they were employed and earned money but because they are not and they do not there is less demand and in consequence the jobs to employ them are not created? This seems easily solved with loans breaking the cycle by creating the demand first.