old school men had higher testosterone. High T causes increased DHT which makes them bald earlier than normal, like how most men who use steroids go bald soon after. Now the increased high T does not always cause the DHT rise, and DHT rise does not always cause baldness, genetics play a large role in that as well, but typically... When working outside with no hair your scalp burns and peels. Hats prevented that, it also helped hide the fact you were bald. Day hats were for shade, night hats were for the ladies.