Yes, they have a less progressive taxation system where low and middle earners are taxed far more heavily.It might. And note that for the majority of Swedish taxpayers the combined marginal rate of income tax and social security tax is just under 64%, so clearly this model is compatible with very high marginal rates of tax.
They also have a very heavily subsidised childcare system so the financial disincentive to work due to childcare cost is (almost) removed.
Between the less progressive income tax system and the subsidised childcare system, and a less generous welfare system, there is no financial cliff-edge for working parents when childcare costs come along.