26 COPs to date have not delivered, so why will COP27 (or even the next 27 COPs) be any different?

It won't and here is why. It's all about the money, and the money is all about who pays for the pollution – the stock put up in the atmosphere since the Industrial Revolution, and the continuing emissions being added now.

The $100 billion per annum promised at past COPs (but never actually fully delivered) is chicken feed compared to what the polluter-pays principle dictates. It is less than the annual dividend of Saudi Aramco. Worse, because the nationally determined contributions (NDCs) measure only carbon territorial production, they don't even properly measure the current pollution. It is carbon consumption – including all those carbon-intensive goods imported from developing countries – that needs to be added back in to determine the true carbon responsibilities. The polluter-pays principle would put a price on carbon emissions and the NDCs would need to shift to a carbon consumption basis, not carbon production, including the carbon embedded in imports. There needs to be both a carbon price on all carbon, imported or otherwise (dealing with current emissions), and compensation for past pollution and the damage it is causing.

To walk the walk, and not just talk the talk, polluters really do need to pay. The real reason why this is not going to happen at COP27, or at the COPs that follow, is that politicians don't get elected to make polluters pay, because the ultimate polluters are us the consumers of all those carbon-based goods and services. If we want to stop causing climate change, the pollution has to be paid for.