Not true. I know of a nurse, who after 30 years of practice, went back for a PhD in another discipline. Its entirely possible, depending on the person.
I know quite a few people in their 40's who are going back for their PhDs.
Listen you uppity cockmonger: I deduced from the available evidence that
this particular applicant won't be accepted into a reputable PhD program, not that
no one of a ripe age can, ever. The latter happens, albeit uncommonly.
It's also worth considering that there are a variety of shit programs with lax standards that one can matriculate into, though this bears on your point rather than mine.
If you ever challenge me again by burning straw formed in my visage, I will flex my 300 pound, rippling muscular physique, hack into government mainframes, and send a DHS predator drone to blow you out of your trailer.