why were there so many less prophetesses in the Tanach than prophets?

Shalom, Thank you for your question. Firstly, you are correct that there are many more teachings in the Tanach from male prophets than women prophets. However, our sages teach us that there were multitudes of prophets whose words were not recorded in the Tanach. About them we have no idea of the ratio of men to women. It could be though, that in fact there were more men than women – and if so, this is probably a reflection on the fact to become a prophet one had to have extensive preparatory learning and spiritual growth. We see this in the “schools” of prophets that are mentioned book of Samuel. Because of the way society was structured in the days of the Tanach, it would have been much harder for women to find time and training for such study. I know of no teaching that indicates that women are less able to attain the level of prophet than men. Blessings.