Like that's ever been an issue here on FR's Balkan threads.
The only thing preventing Serbia from developing its economy is the Serbs - by choosing to cling to a discredited socialist/nationalist legacy, they're getting exactly what they're asking for: poverty and international isolation. Slovenia has used the 15 years since independence to get their economy together, and the results are inescapable to the objective observer.
Slovenia, btw, has an economy "only" ~1/3rd larger than Serbia's, due to there being 5 times as many folks in Serbia.
But hey, it's all BS because it's inconvenient, right?
And Slovenia had the best economy of all, even when it was part of Yugoslavia. If I were them, I'd have wanted to take a walk, too.
But I can recall Slovenia in the 1970's, when an American half-Slovene, half-Serb friend of mine said to me, "Why is it that in Slovenia, they can put up a McDonald's and Tito calls it communism. But in Serbia, they can't even have a farm collective without Tito saying that it isn't communist enough! What is that madman doing?"
Tito was "mad" like a fox.
The Slovenes and Croats, individually, were never any real threat to Tito's power -- he was half-Slovene and half-Croat himself. The Bosnian Muslims and Albanians were never any real threat to his power, either. As a matter of fact, "Tito's Muslims" were an excellent "trading card" for doing business in the ME.
Right after WWII, Tito also fancied himself becoming the "Stalin of the Balkans", and this is why he broke with the real Stalin. It is also why Tito imported Albanians into Kosovo and wouldn't let Serbs return (so he could take over Albania with his homegrown variety). Tito backed the communist side of the Greek civil war, hoping to add Greece to his realm. But this plan never worked out for him and he had to settle for Yugoslavia, alone.
But the only ethnic group who was any real continuing threat to Tito was the Serbs, because they were the single largest ethnic group in Yugoslavia, they had a history of democracy, and they had a huge active diaspora expelled after WWII for fighting against communism.
So Tito kept "his enemies" (the Serbs) closer than his friends. Tito made Serbs into "real Yugoslavs", involving them at every level of the government, overlapping their territories (the Krajina and Dalmatia have only been part of Croatia since post WWII)with the Croats, dividing off Kosovo -- in short, making sure that Serbs were so invested in communist Yugoslavia that they dare not rebel or lose everything dear to them.
American Serbs had been telling Yugoslav Serbs for years that they were being set up to fail because they were the only ones so invested in Yugoslavia, but they wouldn't listen.
And likewise, neither would America listen to anything but "pro-Tito Yugoslavia". The US State Department was more pro-Tito than any Yugoslavs were. Twice initiatives were passed by the US Congress to honor Tito's WWII rival here in the US for saving the lives of over 500 American flyers during WWII, and twice those initiatives were shot down by the US State Department because "it might offend Tito". US Serbs couldn't even get the second in command of WWII Nazi Croatia, Andrija Artukovic, deported. The SOB was living openly in San Pedro, CA for over thirty years and was responsible for the deaths of several hundred thousand Serbs, Jews and Gypsies. Finally, the Jews went after him and got the job done after Tito died, because -- even as Americans -- we couldn't do a damn thing about it.
So the failure of Yugoslavia, post-Tito, was expected. The bloody wars over Croatia, Bosnia and Kosovo, predictable. The Serbs as "the bad guys", likewise predictable.
Sad, but it's been like watching a car accident from a distance in slow motion. Nothing you can do while it happening except help the wounded once it is over.