It does seem inevitable that if you give women rights and the ability to earn their own living, they will choose to have very few children, including in countries a lot less well off than the U.K.. Government policies to encourage women to have more children don't seem to be very effective.
I see it as a very good thing for the planet, although I do think it is sad when women end up childless despite wanting children. We now live in a society which seems to frown on women having babies at a young age. If the norm is now to start your family in your late twenties or thirties, it leaves a very short window for women. I didn't have my first until my late thirties, so I could have easily missed the boat.
I also think people want to give their kids a certain lifestyle these days, which obviously limits the number of children you feel you can afford.
At some point we are going to have to tackle the demographic shift. We can't keep kicking it down the road with immigration. People seem to forget immigrants also get old, and long term, it will just make the problem worse.
I think there would be so many benefits to the U.K. if we would just embrace a gently declining population. A lot of the financial pressure on families comes from having to have 2 incomes just to afford accommodation. If housing prices were stagnant or declining, we wouldn't have to work so hard just to put a roof over our heads.
Maybe people would be inclined to have more babies if they could buy a family home on one average income, as was certainly possible for my parents in their early twenties.
I wish we would look at quality of life rather than how 'rich' the country is.
As to how we pay for an older population, I would suggest focusing tax increases on wealth, starting by taxing all inheritances as income. Nobody deserves to inherit over a million pounds tax free.
Also I think doctors need to have more honest conversations with very elderly people about treatment. Quality of life is important.
Ultimately I hope we can create a society where women can have the number of children they want. It's not for everyone, but my children have been nothing but a joy to me, even now they are teenagers!