Big stadiums, big cities and small countries

Today, many large cities in small countries of central and southeastern Europe have a problem to built or not to build big stadiums. We talk about cost of construction with regard to the current visit of football matches.

Let me give an example of the state in which I live - Croatia.
Croatia is a country of 4,5 million inhabitants. The capital city of Zagreb has with the surrounding area about one million. The second largest city is Split with only 200,000. Yet these two cities have two major football clubs for which 95% Croatians who care for football support.
These are the Dinamo Zagreb and Hajduk Split. For example, I live 100 km from Zagreb and 500 km from Split. Here in my town 65% of people cheering for Dinamo, 30% for Hajduk, ​​while only 5% for the local or any other club.
In Zagreb there is Maksimir stadium. He has 38.000 seats. The Croatian league matches to be used many times only for 2-3 thousand people. But when they play international games, the stadium is full. Last season the stadium was filled and against weak teams like Neftchi, Helsinki and Malmo. Clearly it was full against Real Madrid, Ajax and Lyon. So see a big difference in visiting Croatian league and European matches. Up to ten times. This is because the Croatian league is very weak. Dinamo is champions seven years in a row and it points to a huge difference. Only around 15-20 thousand came to the match against Hajduk.
So, another club is Hajduk Split. They have a nice stadium Poljud with 35.000 saets. Although coming from a smaller town in Croatia have almost the same number of fans as well as Dinamo. And they filled the stadium with no problems until the end when is some important European matches or when they hope that they can beat Dinamo. They have fantastic fans. The only problem is that their club is not even close to organized as a Dinamo.
Besides these two clubs everything else is really bad. There is no one team that can gather more than 5 thousand people. Because that the league is so bad. You know in October that Dinamo will be a champion, and the other clubs just watch how to pay their bills.
To summarized, both of the largest stadium in Croatia are full only a few times in a year and that when they play international games or when playing our great national team.

A similar situation exists in other neighboring states and cities. I'm referring to Belgrade, Budapest, Prague, Sofia ... These are all huge cities with huge capacity, but their states are too small for the top leagues. All of them have only a few clubs with a large number of fans (Red Star, Partizan, Slavia, Sparta, Ferencvaros, Levski, CSKA …).
But all along we can have a phenomenal league. So I think it would be good to make a joint competition.

In this case there will be a need for large, modern stadiums. That could help UEFA giving Euro 2020 in all these countries. Platini has already said that Euro 2020 is held in 12 cities in several countries. We need it more than western Europe. And our potential is huge.