We are splitting hairs here. They are investing their own money into the infrastructure, but it's only enough to keep it going at a more efficient pace.
They didn't buy a utility, they signed an agreement with the government to operate the local public utility infrastructure and operations. The TORs for these agreements are about a quarter of a century old now and about 10 million people out of date.
The point is: they're not making enough money and they don't have a remit over a large enough geographical area to make the strategic changes necessary to cope with demand ss the amount they are able to charge in bills is managed by the government. So the government either needs to allow bills to go up significantly and co-ordinate use of that extra funding nationally. Or more sensibly, it needs to invest government funds in a huge national civil engineering project to modernise our waste water management infrastructure.
If all of the water companies were nationalised tomorrow you'd still have the same problem: you'd have an arms length public body reliant on water bill income to reinvest in infrastructure meaning the investment merely "maintains" and slowly falls further behind demand rather than strategically enhances at the scale necessary.
