
I'll try my best to answer your question, might take some time...
As for why is it haram, When something is declared haram by Allah swt, it is haram, forbidden. My own observation could be, that taking interest is very un-just, the Interest banking basically was devised to control the finances of the world, by first destroying the gold currency, and then moving on to paper money, which in reality has no value, and can be easily de-valued, its just a paper.. Citizens already pay hefty amount of taxes to the govts. and those taxes go to unjust wars and what not, it is just like sucking people's money up, it is a kind of slavery if you look at it, you're bound to return your interest loans and God forbid if you're unable to, the banks take everything you have, and you cannot take another loan to start a business or etc if you arent returning your previous loans at a steady rate I think....
Also it is extremely unjust of govts. to impose a huge ever increasing interest rates while lending loans to its people, because it is the govt that is supposed to serve/facilitate the people, not the other way round. People seem to think now that the banks are helping them get an education/ house etc, but instead the banks are actually buying more and more people into the fold of interest so that the banker's money is Always increasing, and the people are sort of always liable to pay back the interest, via several generations, some even ending up loosing everything they have, to pay back the interest rate.
No good education should cost so high that a person has to resort to loans and interest pay back. But it does cost so much, and that is what i don't like about the current system of the world , it is totally designed for the rich and elite.
Anyhow that is the scenario all over the world and as predicted in the hadith, a time will come that No person will be free from the influence of interest. There are ways around it, and might be difficult, but there are always ways, hope you find them too IA.