I do not think loneliness is any greater among older people than younger. However, I do think, more people of all ages are more lonely than in the past.
Many people are lonely because they have never had and have failed to learn the skills required to reach others and make connections.
When lonely people come onto GN with threads about being lonely and how to meet people, it is noticeable how they either turn down every suggestion made about joining groups, or say they have done that but that they were all cliquey and nobody spoke to them.
Making friends, or at least chatting acquaintances depends on body language, facial expression, and openess that not everybody is born with and some never acquire.
I have often puzzled over the conundrum that it is those who are most lonely, who are most difficult to reach because they do not respond to invitations to come to events, set up to encourage them to join in.