How is that not a (temporary) shortage? When did it become part of the definition that all shortages must be permanent? What if nobody trains to become a cons

How is that not a (temporary) shortage? When did it become part of the definition that all shortages must be permanent? What if nobody trains to become a construction worker (for whatever reason) and then over the next 5-10 years demand goes down because people get used to making do with the buildings that already exist? Is it also not a shortage then?