Unions & collective bargaining is another option - depending on the profit margins of the companies involved.

Basically, if social workers collectively refused to work for the current pay, either social work would be eliminated (unlikely), or pay would rise - either through government subsidies, or at the expense of profit margins.

True. I wonder if social workers would find themselves in the "not allowed to strike" group of government employees.

A lot of social workers are not government employees, there are a bunch of private counseling practices, NGOs, and hospital systems and the like that employ social workers as well. (I’m only familiar with the situation in the US)

But I think your point stands even aside from any regulatory specifics. Asking social workers to strike for better wages is essentially asking some of the most vulnerable in our society (e.g. kids in the foster system) to bear the brunt of our collective underinvestment in meeting their needs. I think that’s less acceptable of an impact compared to stressing out some BigCorp’s bottom line in the case of Amazon or Starbucks and similar