Why did Islamic fundamentalism take off by the late 70s

[Agonized-Statism]

There's a lot of great material out there that explains it more eloquently than me, but basically, Islamic fundamentalists had been propped up by the West in reaction to the unfriendly secular republican Arab nationalism emanating from Nasser's Egypt from 1952 to the 1970s. Despite its socialism, anti-imperialism, and developing world solidarity, Nasser's ideology stressed international non-alignment and was somewhat hostile toward Middle East communist parties- but with Egypt's bloc pitted against the West during the Suez Crisis and the Arab-Israeli wars, there were concerns that the modernizing republican Arab nationalism would become a vehicle for communism in the region. Moreover, the West feared a strong, independent Arab world with full control of its resources.

Arab nationalism arguably peaked in 1958 with the establishment of the United Arab Republic (along with a looser United Arab States adding North Yemen to the Egyptian-Syrian UAR), but Nasser failed to co-opt the Ba'athists and allow Syria the autonomy it desired, so the arrangement fell apart. Egypt still called itself the UAR into the 1970s in the hopes that another Arab union could be tried, but its defeat in the 1967 Arab–Israeli War is considered by most historians to be the final nail in the coffin. The fundamentalist kingdoms that the West was propping up, meanwhile, really hit their stride with oil revenue and, unlike the Arab nationalists, successfully challenged the West with an oil embargo in retribution for the Yom Kippur War in 1973.

Unfortunately in my opinion, Islamic fundamentalism rather than Arab socialism then became the primary vehicle for resistance to Western influence. The US couldn't exactly dump the Saudis, still fearing a resurgence of Arab nationalism (Gadaffi and Saddam Hussein dabbled in it a bit; the Iraqi invasion of Kuwait in 1990 was conducted ostensibly to spread republicanism), facing a new threat from revolutionary Iran (Islamist but republican and Shi'ite), and dependent on their oil. Nor did the Saudis want to cut such a beneficial relationship. Instead, they poured a ton of money into Islamist organizations, and wealthy Saudis like Osama bin Laden became fighters themselves to export it. Again, this happened with US support: the Afghan mujahideen of the 1980s were romantic freedom fighters against an evil Soviet empire who were the moral equivalent of the founding fathers, like a right-wing Che Guevara.

Much like with the strengthening of China, the US ironically built up its own adversary. Common sense solutions like withdrawing from Middle East wars that create power vacuums and resentment or ending support for the bankroller of Islamists, Saudi Arabia, are poorly received because that would require the US to give up some power. Hint, maybe something that just improves people's lives like a global infrastructure development strategy would be great for Western PR. But no, that's too soft on the menace of the week.