I will briefly look at the differences with three different factors namely : Economic strength, political stability and education and technical growth.
1. The economic strength also covers the ability of the government to attract employment to the citizen which empowers them out of the street and give them high standard of living, robust national economy due to exportation cumulating into strong and reliable currency.
2. Show me a country that is ridden in war and I will count their losses for you.
3. Education and technological growth goes together. This is the creative industry which off course helps the country and adds to the GDP either as terrorism, acquisition of best brains from other countries because of good working environment etc.
I think corruption is also the biggest difference of developed and developing countries because politicians stole all the tax money of people...
I don't think corruption can be a factor here because even in developed countries, you will find corruption being endemic in the midst of the people in government. To this extent, I think the difference here is that the developed countries abide to democracy and the law reigns. Some of the factors of such democracies are the rule of law and supremacy of the constitution. So they keep to the laws in the constitution so that, whoever contravenes the law is punished according to the same law. Hence, it is not that there are no corrupt politicians or people in developed countries but they also have the political will to excute judgements including death sentences not withstanding whose ox is gord.
But we need to remember that the developing nation's politicians were super rich than the developed nation's politicians...
Some times I think it is suppose to be the way which could indicate that the candidate is going in government for service having reached the pick of his/career endervour and not to amerse wealth because this is the situation in developing countries, their politicians see government offices as a means to clamp to wealthy status, steal money, acquire illegal properties etc.