That is not out of reach since KSA has reactivated all the civilian and military projects and deals with Turkey during the visit by MBS..@Ghostkiller
Most important thing of an “Arab NATO” would be standardization of ammunition from small arms all the way to artillery.
Although I do agree, joint projects would be quite useful. Imo a drone fighter jet like the MIUS would be a very useful project that could be produced in very large numbers for all air forces in the Middle East.
Then it would be an actual commitment to attacking an aggressor nation without any ifs or buts.