Unless I've misunderstood, what OP proposed is just increasing the tax rate of the existing system.
A progressive tax doesn't result in earning less for working harder; it's only the marginal income that's taxed at the higher rate. So a worker who goes from making $50,000 to $60,0000 only pays 15% tax on $10,000 and has a net take home increase of $8,500.
Unless I've misunderstood, what OP proposed is just increasing the tax rate of the existing system.
A progressive tax doesn't result in earning less for working harder; it's only the marginal income that's taxed at the higher rate. So a worker who goes from making $50,000 to $60,0000 only pays 15% tax on $10,000 and has a net take home increase of $8,500.