UK max state pension according to UK Gov site is 120 pounds a week so 6000 a year. Inflation is the key factor but currently less than 5 %. For a 65 year old couple to lose hundreds of thousands they would have to live a very long time and inflation would have to skyrocket! On current numbers the difference for pensioners living to 90 is much less than you suggest. I disagree with the statement that it will easily be hundreds of thousands.