The difference is power imbalance. A landlord has distinct and easily accessible power over their tenants: they own the tenants home. An employee, conversely, has very little power against their employer. Even a small business has a great deal of power over their employees, and most wage theft occurs at larger ones anyway. Employees can pursue cases of wage theft, sure. But:

- They must use the court system, and do so probably without legal representation unless they can find a lawyer willing to work pro-bono. This requires time and money

- At the same time they’re almost certainly job hunting because while retaliation is (sometimes) illegal, it’s trivially easy for businesses to cite other bullshit reasons for firing people and be entirely in the clear, because that’s even harder to prove in court than wage theft

- If they do manage both of those, they now have a documented history of fighting for their rights as workers, and bosses do not like that. It makes them inherently riskier to hire.