Is it any wonder that Saudi Arabia remains wary, and concerned about Iran?
In Iran’s gross misallocation of economic resources, there is, in Saudi eyes, concrete proof of Iran's continuing commitment to expansionism.
The FT lays out an excellent analysis here of the difficulties confronting Iran's economy—and the Iranian people: A real unemployment rate of 35-40%. Minimal foreign reserves. Widespread poverty.
And yet, Iran still spends billions in Lebanon, Syria, Iraq and Yemen, funding, arming and supporting Hezbollah and its ilk. It has spent billions more on its nuclear and ballistic missile program. Iran is choosing to allocate scarce resources for its military and for external power projection, rather than for the human development of its people when it has very little money in the first place.
There's an old adage: Look at what those who govern actually do, and not what they instruct their diplomats to say (especially, when they say it in English, and when that differs from their rhetoric at home).