Why was only one company prepared to insure a young pilot? Because their perceived risk of a claim was higher than for the average non-pilot of the same age. The company calculated its risk and from that set an amount for the premium. Whether or not that premium amount changes over the years depends mainly on the increasing age of the client.
There are two classes of product that are sold by insurance companies. The first is "insurance". This product returns an agreed sum to the insurer if, and only if, an specified event occurs. Your house, car and CTP policies are insurance policies. These policies have a fixed period for which loss from a stated event occurs. There are so many events that an be insured against that I could not hope to list them all here. However there is another type of product.
The other product is "assurance". This is a product that pays out for a specific reason based on the life of the insured. One product is "Whole of Life". With this type of product, the insurer agrees to pay a set amount upon the death of the insured. Since this product will have a life of many years, the premiums are based on the expected life span of the insured and the sum to be paid out. Basically, teh insurer hopes that the insured will live to an old age, by which time the total of premiums will equal the amount insured. The insurer takes a hit if the insured dies young. Meanwhile, the insurer is receiving money regularly which can be invested and the profits of those investments taken by the insurer. Assurance policies can also be taken out by companies on the lives of employees whose death would adversely affect the company's operations
A similar product is an Endowment" policy. This type of policy is an agreement to pay the insured an agreed amount at the end of a specified period, say ten to twenty years. The annual premium is simply the amount agreed upon divided by the number of years. There is also a bit tacked on to cover a death benefit if the insured dies within the period. This type of policy was popular with grandparents to provide a gift to grandchildren when th child reached adulthood.
Superannuation policies are a sort of assurance policy in which the premium mainly goes into investment, but there is a bit used for death and disability events. The proceds of superannuation are paid out as a lump sum which can be used to puchase an annuity (pension), or not. But most of you are well aware of that.