This is the most striking difference between the less developed countries and the developed countries. The less developed government, when they ascend power usually focus on how to succeed themselves as soon as they get in there. This is why they won't do or create long lasting policies. They don't build long lasting projects, they rather do projects that will easily fade off like roads because they will still be there to reaward those contracts. Those reawards of projects certainly don't fly without having percentage bargained with the contractors (who are friends or relatives for their dirty business to be kept secret) to be remitted into their personal account.
The developed countries are progressive and this is why they focus more on the next generation. They conduct election to produce the best candidate that will better the life's of children unborn.
I'm fortunate to be from a developed country (the UK). However we have the same issue, as do other developed countries. It does depend to an extent which party we have in power, but there is a huge tendency towards short-term thinking. It's all about what will make them look good today, and forget about tomorrow because that will be someone else's problem. There is a huge amount of wealth appropriation and corruption, too. Perhaps less than in less developed countries, but it's certainly still there. I could go into depth with examples of privatisation and systematic asset-stripping, cronyism, corruption, lobbying etc... but I won't, because I think we have a great example of how governments act, and one where we can compare all countries simultaneously, because they all face the same problem: the Covid 19 pandemic.
Look at countries that have acted quickly and decisively, caring more about the health of the population, and smart enough to understand that a short-term initial economic hit is far more beneficial for long-term economic health than waiting until it's too late. You won't find many developed countries giving a good example here, certainly not the UK, not the US, not most of Europe.
Structure and institution: This is not same here. Structure and institutions are fortified so that no government can manipulate the system, policies without facing the law. This is a progressive system and a big difference.
You do make a valid point here. This is indeed a crucial difference, and a reason that developed countries are somewhat less corrupt (it reduces the problem a bit, but certainly doesn't eliminate it). The point is that the people in charge want to be just as corrupt - because people are the same everywhere - it's just that our democracies are somewhat older, and have these safeguards against the elite. One reason that poorer countries are more vulnerable is because they are younger and less stable, which is often a consequence of historic colonialism and exploitation by the richer nations.