If a person reads a lot of theory about how to swim, different types of techniques, other people's written experiences etc., can they swim if thrown in a deep swimming pool? Or, at least, be able to swim enough to reach the steep end and save themselves from drowning?

By "a lot", I mean spending over 6 months to a year, gaining theoretical knowledge. And when we throw them in the pool, they are willing to try it, as in, "I have learnt enough, and I am willing to try it out."