If you attended lessons for 4 years, and trained every day at home, how much practice have you done?
180 training sessions in class (45 x 4) + 4 years daily practice at home (365 x 4) = 1640 training sessions.
That is almost 10 times the amount of practice relative to simply attending class.
Naturally, there are other considerations, such as: how many minutes or hours of daily training do you undertake?
What is the quality of that practice?
But you get the general idea...