The number of shotos in the game doesn’t even matter that much.
In October 2016, when there were only two shotos in a 22 character roster, those two shotos held a combined 27% usage. Less than one-tenth of the roster accounted for more than one-quarter of the roster usage.
In December 2016, the game brought its roster to 23 by adding a third shoto, Akuma. The three shotos posted a 35% usage. While this usage would drop over time, these characters consistently stayed at the top of the usage charts, only suffering bumps in the months when a new character was released.
In November 2018, even though the roster now held 34 characters, the top three set of Ryu, Ken, and Akuma posted a combined usage of 26%. Again, less than a tenth of the roster accounted for more than a quarter of the roster usage.
So it isn’t a matter of there being a lot of shotos in the game. Indeed, the whole reason there are so many shotos in the game is most likely because shotos are so popular.