Not that privatisation is the answer, nor that being public was at fault, but I'm not sure rewriting history is helpful.
Looking at UK water companies being privatised so their owners can stuff them full of debt to get around the profit caps is probably a better case study.
Profit percentage caps are silly because the obvious way to make more money is to make the entire service more expensive by wasting money, this increasing turnover, thus increasing the size of that 4%.
Monopolies being privatised doesn't seem super helpful either, but hey, that's the UK for you.