Do men quit making sperm after a certain age ?

No

Only if they have had prostate cancer or problems with the prostate.

No, I'm a fit and healthy 66 year old and I still masturbate once a week and can still squirt my semen onto my bare stomach and chest.

Men continue to to make sperm even after 70, but testosterone level may be low.

No, old men with healthy genitalia can still impregnate a woman. What men ejaculate consists of two things, semen and sperm. Sperm is what gets shut off if the man has a vasectomy. Semen will still be ejaculated post vasectomy. If the man develops prostate issues, the course of action there is to remove the prostate (be it with surgery or radiation) which will remove the semen from the equation. As men get older, getting an erection can become more difficult as you can probably guess from the never ending adds of ED drugs.

no

I wish

Sperm production can decrease with age, but there is no sudden end date as there is with women, unless of course the guy gets a vasectomy.

Yes