Bukowski isn't the best example because while he became successful late in life, he'd been working on his craft for decades earlier. He didn't take up writing at 50; he just started getting published at 50. He already had decades of experience.
If Bukowski had never written a thing until he was 45, then it would make sense
He wrote of being refused by publishers when he was younger. It was his perseverance that brought him through. He never gave up on writing or drinking.
Ray Kroc was already a successful salesman by most ordinary standards, and then became extraordinarily successful. Walter White narrowly missed out on a place as a co-founder of a multi-billion dollar pharmaceutical company. Neither is really a late bloomer.
If Bukowski had never written a thing until he was 45, then it would make sense