There will never be an ideal solution until the problem is addressed with individual circumstances in mind instead of the 'one size fits all' schemes which are dreamt up by politicians and civil servants who have never been (and will never be) short of a bob or 2 in their entire lives.
Never say Die is surprised that many people are (will be) relying on the state pension in retirement. There can be many reasons for this - ill health during their working lives, stay at home carer, working in the (until recently) non-pensioned voluntary sector, self employed or part-time so did not qualify to be in a works pension scheme. For those in these categories who took out a self funded private pension there was the pensions raid carried out by Gordon Brown which wiped 20-30% off the expected value of the annuity. In our parents' day, small business owners either sold their business for a lump sum to fund their retirement or leased the business to someone else to provide a steady income. This does not happen now as there is no financial support available to help an existing business continue while grants/loans are available for setting up a business from scratch.
Of course those who enjoy and want to carry on working should be able to do so, but for those of us whose work is simply a daily chore to be completed in order to eat and pay the bills, there is surely a time when 'enough is enough'. As to the nature of the work involved it does not all rest on heavily physical tasks. Casting my mind around I know of an early retired Potter and a musician who both succumbed to arthritis in their hands, also a watch/clock maker/repairer whose eyesight deteriorated beyond the help of magnifying lenses. I suppose the powers that be would want them to retrain in their late 60s.