Sadly not, the tax system is far less equitable than that. You stop paying NI at about 45k, so the rates are 13% from 8-12.5k, 33% to 45k, 41% to 100k, 60% between 100 & 120 k) then 45% over 120k.
And IR35 is hugely abused. I had three desktop people doing grunt work for me a while back, one folded his company every two years to do something dodgy with tax, one paid his money into his personal bank account, the third didn't even seem to attempt to pay tax. None had specialist skills, they were all contracting as they could earn more and avoid tax.