>>262452multiple reasons - for one, tactical failures on abdelnasser's part, wrt his wars against Israel and in yemen.
Also, effective resistance and/or co option of the ideas from the reactionary bloc in MENA - at that time, primarily saudi arabia, jordan, and iran (gulfies were generally too small then)
Also again, absolute failure of arab communists/the USSR to continue pushing the movement, and allowing it to stagnate
another also, the "military coup" nature of their revolutionary strategy generally limited participation by the working class (except those that joined the military), meaning governance was generally speaking more hierarchical, and the proletariat was less able to resist "revisionism" from Anwar Sadat
FINAL ALSO, the CIA funded islamism.