There's obviously different strands of privatisation.
The sale of gas/elec/water/BT were all condusted at opening share prices that were well below the market valuation (the proof being the immediate increases in share prices). The claim is that they were deliberately sold off on the cheap to a) ensure that the share issues were a fully taken-up success; and b) to guarantee profits for investors (many of which were supporters/donors of the Tory Party)
I think it's clear that, in terms of creating a proper market for consumers, the BT sale is the one that most closely creates this - although that has depended on the advancement of new technology (and most providers still rely on the old BT - now Open Reach - infrastructure network)
Water is ridiculous privatisatrion model. Pure monopolies were created. OfWat were created as regulator, but were set up to be all but toothless. The result is that, since the 1989 privatisation, water companies have:
~ been able to hike prices way above inflation
~ not build any major reservoirs since before privatisation (despite the UK population increasing by over 18% in that period)
~ paid out £57bn in dividends to shareholders between 1989 and 2020.
The gas-electric has created a market for suppliers. And, prior to the current problems, most made some profit. But the biggest beneficiary is behind the scenes. Privatisation split the provision of gas & elecricity into suppliers and the generation/infrastructure. The structure has changed a little over the years, but the infrastructure - the gas pipes/electrcity cables to homes and business, etc - is owned by National Grid plc. They charge the supply companies to use the infrastructure. Again, they're a total monopoly. And they've taken full advantage, with their profits generally ranging between £2bn and £4bn a year.
Personally, I think we need to nationalise water as a priority. Especially given climate change that has the potential to disrupt supplies here. That £57bn leched out of the company should have been used to replace crumbling infrastructure and build some more reservoirs, not line the pockets of fat cat parasites.
Then nationalise National Grid. Keep the supply side privatised.
With both the water companies and National Grid, we need to minimise the amount payable in compensation to shareholders. Ideally find a way to perhaps index-link the initial share-price and pay that per-share, rather than the current share prices. Or perhaps impose draconion regulations - including forced investment and lower prices - to make them uncompetitive, driving down the share price to an acceptable level.
With the railways, Network Rail is already in public ownership. With the TOCs, the most cost-efficient way is to systematically take control of franchises as contracts expire for each current TOC.
The other main strand of privatisation is outsourcing of services. Rewind 40 years and all the public services were provided by in-house workers, employed by the public sector with decent salaries, secure positions, good T&Cs, pension, sick pay, etc.
So a private company takes over provision of the service, being paid at most what it previously cost the sate to provide the service via a public sector workforce. The owners/shareholders want to extract a profit from the money they are paid to undertake the service, and senior execs/directors also take salary packages bigger than the former public sector managers, so that's immediately a chunk of money diverted away from the provision of the service.
The myth peddled is that the savings are made from 'efficiencies', but examine those efficiencies and it's basically the workforce who pay the price. TUPE is supposed to offer some protections, but it's easily got around. The first step is usually a reduction in the workforce, meaning the remaining workers have bigger workloads. Any new staff will normally be on worse contracts/pay. Increased use of temp/agency/ZHC workers. Then they start nibbling away at T&Cs and pension entitlements and sick pay and holidays. Staff become demoralised and leave. Replaced by temp'agency/ZHC workers, or by workers on worse pay/T&Cs.
You end up with the situation that any savings in the overall cost to the state of the provision of the service are miniscule - but shareholders extract big sums, as to the senior execs/directors. And what were once good jobs are now in the McJob territory.
The result is that a demoralised, often inexperienced, low-paid workforce with high staff turnover, delivers a worse service to the public.
Is it a coincidence that hospital 'super bugs' emerged once pretty much all hospital cleaning was taken away from fully-employed hospital cleaners and handed to private cleaning companies whose main aim was profit maximisation?
You look at the crises in elderly care provision. Go back 40 years and every local authority ran its own care homes. Yes, there were private care homes (usually with high charges), but the majority were public sector. By the early 00's, the programme to sell-off care homes was well underway, and now there's barely any care homes in the public sector. They're nearly all privatised - again, with the shareholders and senior execs/directors removing [collectively] £billions each year in dividends and high pay packages. £billions that could otherwise be used to pay workers properly to end the staffing crisis.
Let's be clear, privatisation is nothing but a device to transfer money to the wealthy at the expense of the workers.
The entire 'efficiency' myth is a misnomer that, sadly, all too may people swallow.