Why do some countries outperform other countries in certain sports despite having a smaller population?

A country's success in a given sport at the international level will depend on a number of factors other than population alone. While a country's population is a good identifier for the total selection pool for high performing athletes to come from, it is one of many factors. A country's founding history, climate zone, and GDP are other notable factors in sport performance. 

A nations history plays factor as many sports are baked in centuries of tradition. For example, Cricket, which is believed to have originated in England is most popular in countries that were originally British Colonies. Long traditions such as this set specific sports into the culture of a nation, increasing the percentage of the athlete pool that it can pull from and can increase the level at which that nation is competitive. 

Climate zone can also influence the competitiveness of a country in given sports. Norway, fore example, earned the most olympic medals of any country in the 2022 olympic games with a total of 37 medals. In the summer games of 2020 (held in 2021), Norway ranked 20th overall with just 8 medals. Norways Climate and Topography have led winter sports to be extremely popular, and Norway has over time developed elite programs in cross country/nordic skiing, speed skating, curling, biathlon, and ski jumping. 

A nations wealth will also influence performance in sport at the international level. This occurs predominantly for two reasons. First is that more money enables larger budgets on equipment, coaching, player development, participation in international circuits, data insights, medical staff etc. that over time create a performance separation from those who can not afford these things. Second is access to sports, many sports are quite expensive some examples include snow sports, gymnastics, swimming, hockey, and polo. Nations which can not afford to provide the facilities or support to develop athletes will often fail to draw a large talent pool and not be competitive at the international level.