Meir Javedanfar in The Diplomat:
By blockading the Strait of Hormuz, Iran would in essence be declaring war against Persian Gulf states and members of the Persian Gulf Cooperation Council, many of whom use the strait to export oil and liquefied natural gas.
Not only would such a move place these countries squarely in the U.S. camp, but it could also backfire by making Iran look weak if it didn’t follow through. It’s no secret that Iran needs the strait to export its own oil, and it’s hard not to see Iran backing down under pressure of its neighbors to lift a blockade to help its own economy. In doing so, it would look weak in its neighbors’ eyes.
Blocking the strait would also likely push these same neighbors to consider a pipeline into the Arabian Sea, bypassing the Strait of Hormuz, a move that in the long run would undermine the strait’s strategic value to Iran.