age discrimination in hiring is real and could be at play. There are advantages and disadvantages to hiring an older/more experienced individual.
sometimes the perception is that an older individual typically ( that does not mean always) cost a company more in that they dictate a higher salary based on their experience , they have more lost time due to illness, greater costs in health and dental benefits for them, spouses and children. Somebody 60 might only have 3/4/5 years years left to work whereas a 21 year old has 40 + years so companies might not want to invest in an older individual and have them leave . ( young folks can leave too though) Different in your case as you have experience in the job so the upfront training would be nonexistent but a real consideration in many jobs.
Of course there are innumerable advantages as well to hiring a seasoned individual. Experience, judgment etc all can be valuable
You are not alone though. My buddy just turned 50 last year and was laid off in May after 23 years with a Global technology firm. With new labour laws he is still getting full salary and help to find a new job but he wont be making 200k with stock options and is competing against University Grads for jobs that pay 80- $100k that he is grossly overqualified for.
seeing more and more friends in same position, long tenure , big salaries but being let go as the company can hire 2-3 young folks for the price of their compensation.
bottom line is you never know what goes on in the minds of an hiring panel so don't beat yourself up. Move on and look for something else. As i've opined several times before, don't settle for a job you don't like or wont be happy in. Money isn't important, happiness and quality of life is. If you are happy in the golf field , stay there.