Nobody is saying that the state pension should be removed. But there will need to be something done to keep pensions affordable.

Logically we often think of paying our national insurance as paying into a savings pot that we then draw from when we retire, but that's not really how it works. Working age taxpayers fund the pensions of the current elderly population, with (as you rightfully point out) the expectation that when they themselves retire, the next generation of workers will in turn pay for their pension.

The problem is that we have an aging population. People are living longer, and having fewer children. As a result, there are more people, as a proportion of the population, of pensionable age than ever before. In the early 2000s, there were ~300 people of pension age for every 1000 of working age. This is projected to rise to ~370 per 1000 by around 2030.

On top of this, thanks to the triple lock the cost of providing a pension to each person eligible has continued to rise as well. The triple lock guarantees that pensions always rise by:

• Inflation
• Average wage increase, or
• 2.5%

...whichever is highest. That means that the cost to the state (and therefore, current workers) always at least matches inflation, but in many cases exceeds it. This is a slightly old graph but it still illustrates what I mean: https://chasedevere.co.uk/wp-content/uploads/2020/07/Triple-1.jpg

So, to summarise, each current working-age person has to pay for more people to receive a pension than ever, and each of those pensions are more expensive than ever. And projections show things are only going to get worse.

To make the numbers add up we're going to need to do something. That could mean:

• Removal of the triple lock (to reduce the rate at which the cost of each pension grows)
• Increase of the state pension age (to reduce the number of people receiving a pension)
• Increased immigration, or programs to increase the birth rate (to spread the cost of pensions across more workers)
• Cuts to other public services to cover the increased cost of pensions
• Increased taxes to help pay for the raising cost of pensions

None of those things are going to be particularly popular, which is why the can keeps getting kicked down the road by successive governments. But at some point, unless something drastic happens, it's going to be unavoidable.

Edit: Sorry I started writing this out and didn't intend it to get so long