While it is certainly interesting and enlightening to know what some of masters practiced, I think it is more complicated than that.
Every person is different, and come to learning music with a different set of strengths and weaknesses. The important thing is to figure out what works for you, how to play to your strengths and to overcome your weaknesses.
One person might find that technical facility comes very naturally, but has difficulty with aural perception. Another might find that they have good ears, but have difficulty grasping theoretical concepts. One person might just play classical etudes all the time while another might spend most of their time improvising, but they come to similar results.
I think that half of one's practice time, especially when starting out, is really about figuring out how to practice effectively and what works for them. The other half is usually dealing with the mechanics of playing the instrument and improving aural perception.
Practicing as much as possible is key. There is a commonly repeated maxim nowadays that it takes about 10,000 hours to become exceptionally good at something. If you treated practicing like a full-time job (8 hours a day, 5 days a week), it takes about 5 years to get to that number. Whether or not it's an accurate assessment, it does give a rough idea of what is required.