There is no doubt that what Saudi Arabia is doing with Qatar is not a simple cut for diplomatic relations, but an assassination. Saudi Arabia has prevented Qatar from using airspace, water and borders though it almost share all borders with it.
On the other hand, Iran is not a very good alternative since it will be a higher cost of transportation. Therefore, Saudi Arabia has given the worst hit, followed by the United Arab Emirates and Bahrain.
As for the Egyptian decision, it came too late following Egyptian-Saudi agreement during the secret visit by al-Jubeir, the Saudi foreign minister to Egypt, on the night of the Egyptian Gulf turn against Qatar. We still remember what happened in 2015 when Egypt accused Qatar of involvement in the killing of the 21 Christians in Libya, and terrorism in Sinai and Libya. At that time, members of the Gulf Cooperation Council refused the Egyptian statements and forced Egypt to withdraw its accusations.
Yet, there are many reasons behind cutting diplomatic ties with Qatar. First, Qatar has good relations with the terrorists of all kinds, but one of the four countries in the Arab ally has very good relations with the terrorists and one of its citizens was the leader of al-Qaeda.
Other people may think that Qatar is trying to overthrow current regimes in several Arab countries by supporting the Muslim brotherhood in Egypt, Libya and Syria, which is also the same policy of couple of countries in the Arab ally. Moreover, this has been a fact for a long time and these countries have ignored it for a long time.
These reasons stated in the statements of the Arab ally condemn some countries for being late and for having the same position. The truth is that other reasons lie behind that position that we shall talk about later.
