WaPo:
for many child-care workers, often hired with little more than a high school diploma, returning to school is a difficult, expensive proposition with questionable reward.
...
unlike in most professional fields, prospects are slim that a degree will bring a significantly higher income — a bachelor's degree in early-childhood education yields the lowest lifetime earnings of any major.
Center directors have few resources to tap if they want to reward their better-educated employees. Many parents in the District are maxed out, paying among the highest annual tuitions nationally, at $1,800 a month. And government subsidies that help fund care for children from lower-income families fall well below the market rate.