Simply because as a matter of fact China still has plenty of rural surplus laborers and people are talking about a magnitude of more than 200 million - so you know from national-wide point of view, there is plenty of labor supply there.
The government should create more jobs in the manufacturing and service sectors as part of it ongoing campaign to reduce the country's rural population.
There's only one conclusion: Continuing to bolster labor-intensive production and exports is the only viable means for China to absorb its surplus labor and improve rural living standards.