For me it's because these other small countries have boys who are willing to get out of their comfort zone and move to different leagues and countries and test themselves against better teams and imbed themselves in different footballing cultures. They have more ambitious attitudes than us.
Look at the Belgian league?
The Tarriers tore apart the Belgian champions away but yet Belguim have an amazing group of players? Because they players knew playing in their diddy league isn't going to improve them.
Scotland players are too comfortable playing in the shitty SPL and English championship and don't want to seek out moves to Germany, Italy, France and Spain like the Belgian boys have done and use that to spring onwards to much bigger clubs playing for major league titles and champions league crowns.
Nah, Scotland players are happy settling for finishing mid table championship or winning a one-team pishy league with the tarriers so they can still kick about with their pals like a bunch of neds.
Oliver Burke moved to Germany but instead of getting his head down and busting his arse for a champions league team team he reverted to type and fucked off to a mid-table EPL team going nowhere.
Russian Football have the same issue.