Pakistan has always let the Saudis down from their perspective. The two Gulf wars and the Yemen expedition are cases in point. We were asked to provide support in the second Gulf war, we did not even as a token presence.
That is one of the reasons, besides many others, that KSA is warming up to India from a military perspective. With the new look outward, more religious tolerance, India has a place in the strategic thinking of KSA viz a viz their own security.
Pakistani political elite and establishment, as always, calculated things from individual perspective (reelections, popularity, religious/sectarian backlash etc. btw the religious extremism was created by one of the usual suspects in the "ruling" cabal) instead of as a national long-term policy.
Our national policy on foreign relations is a joke at best, looks like it runs on a day-to-day basis and from one crisis to another. There is no thirty-year strategic plan in place that directs the country towards a goal that serves long term national strategic interests.