Here's a logical step you skipped: A blind matematician can do revolutionary work in mathematics. He is highly unlikely to do revolutionary work in agriculture.
Interesting example, as there was an article on HN front page 10 days ago about exactly that - a blind person doing revolutionary work in agriculture. [0][1]
[0] https://www.bbc.com/news/articles/c4g4zlyqnr0o — "I used Lego to design a farm for people who are blind - like me"
[1] https://news.ycombinator.com/item?id=46502269