I don't feel that any of the investment options available to us fall into the "complete non-sense" category. It is very easy to find faults, but can you also give some positive aspects of Endowement plans.
Investing in equities is not everyone's cup of tea. Also you write eloquently about diversification, why not invest a portion of money in endowement plans? You can purchase the plan from a relative of yours who sells it for living. It will provide him income in the form of commission. Isn't that a good thing?