The Shaolin Sect had a really small territory. The number of disciples they had only numbered around fifteen to twenty thousand as well.
Compared to the other Holy Sects that have over a hundred thousand disciples in their Main Branch and a few tens of thousands in their side branches, the Shaolin Sect indeed seemed small. As for their side branches, they had none.
The reason for the low number of disciples in the Shaolin Sect was because of the sacrifices one would need to make after joining.
They would need to abstain from worldly desires, which included alcohol, wealth, and sex.
Not many people would want to forsake those things even if that meant joining the most powerful force on the Eastern Continent and learning some of the most well-known Martial Arts Techniques.