Yeah. And so is the homeless population. Pretty soon the numbers will come in showing increases in crime, poverty, unemployment and incarcerations.
That is a migration issue due to the different state laws. It is due to homeless people moving, not the creation of more homeless.
If you suddenly made liquor illegal in your state, the alcoholic homeless would migrate to other states. However, it would create worse problems that come with prohibition.
When more states abandon pot prohibition, there will be no incentive for homeless addicts to migrate for that reason.