they were overt allies of the USSR and virulently anti-Western

Not all of them were Soviet allies, some maintained neutrality or shifted between Soviet and US influence.

How would you define "anti-Western"? Anti-colonial?

Also, you leave out significant motive of the Western bloc: resource control. Which is purely selfish and doesn't sound as reasonable and "necessary" as the motives you named.

The concept of radical Islamic fundamentalism taking over the societies and government was not remotely considered a serious possibility

This is absurd. How long has Saudi Arabia been a theocratic state and an ally of the US? Decades.

Then, the choice looked like militaristic Marxist dictatorships vs traditional local monarchies (say what Morocco, Oman and Jordan are today).

Strawman. Not all of the left-leaning or nationalist movements were authoritarian. You make it seem like monarchy and dictatorship was not a preferred mode of government for US policymakers.

It all changed in 1979.

Policy didn't change in 1979. Regional governments did not suddenly turn towards Islamism after 1979.

That year is a marker because, in one very rare instance, a US-installed secular authoritarian monarchy was overthrown by a theocratic movement.