That's the thing, we simply don't know their impact (or at least, I don't know) - how much extra revenue they raise, can that be earned through some other tax that produces less distortion, do people at the edge actually choose not to work etc?
As an example, I fell off that cliff last few years. Number of my colleagues still are. It made no difference whatsoever in our decision to work (or not), and as far as I can see, no one works any less because their marginal tax is high. We occasionally talk about money, bonus etc, but this has simply never come up.
But I don't project my own experience as universal response, claiming no one affected by the tax cares. Surely some do; some don't.
Unless there is some impact analysis, we will not know.
One thing I am certain though, this is not what caused uk productivity to stagnate for the last nearly 15 years. That is over a decade lost!
Other rich nations have their own problems, but nothing as acute as what we have in our hands and we are doing practically nothing about it. Manager decline again 