Hmm, I’m not sure I buy it, because I’m not sure what additional effort applied to tax administration looks like.
Perhaps we could be optimistic about people and assume the amount of real, legitimate tax fraud and evasion is pretty low. If we took the latter scenario you present—increasing efficiency means the same amount of people will do more work—and assumed this effort is instead applied to decreasing the number of random errors (which might result in someone overpaying or underpaying), we wouldn’t necessarily expect to see a change in the expected value of the taxes. But, it could be “better” in the sense that it is more fair.
Perhaps we could be optimistic about people and assume the amount of real, legitimate tax fraud and evasion is pretty low. If we took the latter scenario you present—increasing efficiency means the same amount of people will do more work—and assumed this effort is instead applied to decreasing the number of random errors (which might result in someone overpaying or underpaying), we wouldn’t necessarily expect to see a change in the expected value of the taxes. But, it could be “better” in the sense that it is more fair.