There may be some other factors as to USA based airlines offering services to Africa and Middle East (except Israel). There are also many other places they can serve with a lot less hassle and make money with.
When PanAm and TWA served those areas, there was regulated pricing as to international routes, as well as subsidies from the USA government to make sure a USA based airline served those places for image purposes during the Cold War era.
There wasn't the hostility in the past as we see today against the USA. There are now several solid established airlines based in Europe as well as in the Middle East & Africa that have better connections, fewer hostilities directed at them. Don't forget that PanAm and TWA were important to the starting of many airlines thourghout the world or their re-establishment after WWII.
As to the corruption issues, the USA has a number of laws on it's books that prohibit bribery and payoffs to foreign government officials and corporations, thus limiting the buying of access to routes, security and labor peace.
Security of people, crews, their bags, aircraft and when on the ground isn't a good place for an American based airline with today's hostile political enviroment. American companies and government posts are big time terror targets as has been shown over the last 25 years. This also adds to the costs of operations. Union rules, cultural and security issues would make it difficult to have staff based in many Middle East and Africa countries.
Real life yeilds in the coach seats would probably be poor. Most of the money making coach business would be seasonal, so most coach fares would probably have to be low to fill the seats and would thus limit profits overall.
Many countries have their own 'national' airline, often partially government owned or subsidised and want to protect it.
Language is another issue, as few in the USA know another language beyond English, and are very unlikely to know Arabic, African languages and their many variants. This makes it near impossible to recruit staff in the USA.
Equipment support, manintenance would probably require a lot of new and expensive investment. BA
, and regionally based airlines have already have that in place and may use different equipment components than USA based airlines would use.