You are correct it has to do with the slowness of the cancer and not "you are not valuable any more." My grandfather developed prostate cancer in his early 80s and the Docs told us, "he will die with it but not from it." And that forecast came true. I don't recall his cancer being aggressively treated and the cancer may not have been treated at all, just the symptoms which were to the urinary function. He ultimately died at age 89 and the cancer wasn't his cause of death.
My father has the same symptoms now at age 82 that Grandpa had at same age when he developed prostate cancer. But Dad has prostatitis. The treatment is pills and they don't seem to be totally ameliorating his symptoms. He is urinating frequently. So with him because of symptoms and family history they are keeping an eye on it which is why he had both the biopsy and the cystoscopy. These are not fun tests and they are definitely not risk free.
Prostate cancer has the highest 5 year survival rate of any cancer- close to 98% and just a percentage higher than thyroid cancer. I had thyroid cancer stage 3 and have survived it by 5 plus years now. Both of these cancers are usually slow to metastasize, but in my case it did metastasize into 2 lymph nodes. The 2 nodes and the thyroid were surgically removed and I was then irradiated with 157 millicuries of radioactive iodine and was good to go. My uncle who had prostate cancer in his 60s did have a prostatectomy which is how they often treat it when it hasn't metastasized out of the prostate which it usually doesn't. He took a sabbatical from his college professor job one semester. After surgery he had temporary severe urinary incontinence and wore adult diapers for a while. But he got over that and is now healthy and retired and 73.
I must report that my neighbor who passed away a few months ago same age as me (57) had undiagnosed prostate cancer which metastasized throughout his body and into his bones. By the time he had any symptoms was too late to do anything. He was an alcoholic and didn't take good care of himself and was unfortunately involved in a messy divorce when he found out he had the cancer. I think this was an unusual outcome. He probably hadn't had a PSA test in years. I didn't ask him but in talking to him I got the impression that he never thought anything was wrong until it was too late and in his bones.
It was same with my cancer as far as no signs or warning. My doctor saved my life on routine annual exam by spotting swollen lymph nodes in my throat which I never had noticed nor would have noticed despite shaving the area every day. No symptoms and the swelling was imperceptible. Cancer can sneak up on you silently. It did on me and probably did on my unfortunate neighbor God Rest his soul.