There's elements of this...We have enough people here - why not train them up to do the trades. Incentivise it so that tradies want to take on apprentices. Less people + less housing stress.
But there's also a shortage of workers in general. The Australian unemployment rate is currently 3.9%, which is close to the record low of 3.4% (Oct 2022). We simply don't have enough workers in Australia to do all the work that needs doing. Some areas, with specific skills, have even more problems - and construction trades are among these.The apprentice system has been on the decline for years with both sides of government. Also, I know of people that are applying for trade jobs with dodgey credentials.
Contrary to your assertion, we really don't have enough people here.