Updated from two posts in 2016.
Age discrimination can be applied on an individual basis – older people being passed over for jobs; being patronised as “lovey” and “dear” and generally being seen as a stereotype rather than as mature and experienced individuals. But what I am calling “age-phobia” is much more high level and generalised. One good example is a quote from the Sydney Morning Herald a few years ago:
The ramifications (of ageing) could be serious as the elderly become an additional burden to the traditional scourges of poverty and disease. 
How does it feel to be compared to malaria or the Covid virus?
More recently, Nigel Latta hosted a Hard Facts episode in which he was made up to look like himself as a “really old” man of 70 (he is in his fifies now). He recoiled in horror at the bald head, the straggly grey hair and the lined face. The message was; we don’t want to think about getting old because it is so horrific; we will become ugly and repellent. Then we saw old people lolling around in the sunshine, enjoying a life of dependence on younger generations. But some of those interviewed were saying positive things about their lives. This was greeted with amazement by Latta. I couldn’t help feeling that he stoked up inter-generational competition, if not outright antagonism. Age-phobia? Do you agree?
“Transhuman” is a book by Ben Bova (a science fiction writer, who died in 2020, aged 88). It features a biochemist who develops a treatment to reduce cell ageing and to cure cancer. The FBI and US government try their best to block his work, locking him and his colleagues up in a military base in the Arizona desert. This is because the innovation will allow everyone to live to 100, 120 or even 150. It will, according to the powers that be, “bankrupt America” in health insurance costs and pension support. Of course the elite – selected people, including themselves- will benefit, but not the masses. The protagonist manages to escape and distributes his findings in scientific publications, to my relief. I was expecting the FBI to assassinate him. It may be a feasible scenario based on age phobia and the assumption that old age inevitably brings dependence and disability.
Sure, there is more acknowledgement now of the contribution which older people can make, economically and socially. But age phobia is not dead. It rears its head with every mention of demeaning words used for older people – wrinklies, grey-hairs, geezers, codgers, fossils and fogeys – even “elderly” comes with connotations of frailty and vulnerability, as shown in the 2020 Covid 19 lockdown period. The death rate from the pandemic itself has even been named “the boomer remover”.
There has been ambivalence about ageing for millennia. On the positive side, throughout time leaders have been greeted with “Long Live X!” The Old Testament is full of statements in which long life is seen as a reward from God for goodness.
The fear of the Lord prolongs days: but the years of the wicked shall be shortened (Proverbs 10:27).
The classical age brought down the perceived age of highest (male) development – Hippocrates said 56 and Aristotle 35. Shakespeare, in the seven ages of man speech, is not complimentary about old age. His sixth age is “the lean and slippered pantaloon…. his big manly voice turning again toward childish treble”. And the seventh and last scene of all – “second childishness and mere oblivion. Sans teeth, sans eyes, sans taste, sans everything.”
This characterisation is well known, but I like the Grimms’ story (early 19th century) quoted by Simone de Beauvoir.
God set 30 years as the lifetime for man and animals. The ass, dog, monkey wanted this reduced to, respectively, to 18, 12 and 10 years. Man asked for longer – so he was given 30 years as a Man; 18 as an ass, carrying burdens and feeding others; 12 as a dog, growling; and 10 as a monkey, without wits, making children laugh (adding up to 70).
Nowadays, there is still ambivalence. “Old” can be a term of endearment – “good old so and so” we often say. But “dirty old man” is not complimentary. I feel that the term “elderly” should only be used for the very frail and dependent. As longevity increases, more people are living to 100 and beyond. On this basis the sixties decade is “middle aged” – 75 is the new 65. Are we applying “elderly” to an age group spanning 35 years or more, and two generations? Cartoonist Tom Scott (in his seventies) rejects the term. He says his generation is tough. “If you dropped a nuclear weapon on downtown Auckland, out of the rubble would come cockroaches, rats and baby boomers.”
 Jerome Socolovsky, Greying of humanity a threat to world budgets. Sydney Morning Herald, April 8, 2002.
 And the very worst that I have heard -“pre-dead”.
 The Seven Ages of Man speech in “As you like it”
 In The Coming of Age (1970), Simone de Beauvoir presents a study spanning a thousand years and a variety of different nations and cultures to provide a clear and alarming picture of “society’s secret shame”–the separation and distance from our communities that the old must suffer and endure.