Why is job training such as upskilling and reskilling so important?

The degree of importance of job training differs based on the government as job training is much more important in a capitalist economy versus a communist economy.  Assuming a capitalist economy, job training is important because of market dynamics, supply and demand.  In this case, demand are the available jobs and supply are the skilled workers who provide work in those jobs.  As technology advances, new innovations are made and cyclical market segments ebb and flow, the demand for highly skilled workers changes.  Upskilling is important as it helps workers to maintain valuable skills in their given field and the goal is to keep up with the technology advances in their respective field.  Reskilling is most often more closely linked to cyclical market forces where the demand for jobs in one field go down and another go up; reskilling is acquiring skills in the field with growing demand for jobs when a worker possesses skills in a field with declining demand for jobs or their skills.