it's not that anything really changed. the united states still has naval dominance, but they appear to have allowed the iranians to put mines in the straits due to not foreseeing it happening. i warned you when this started that the obliteration would have to be complete and immediate, or it would open up opportunities to get in. anything iranian operating in the gulf should have been immediately bombed; it seems like it wasn't. the iranians themselves will suffer the most from this, so i can see how it didn't seem like a real threat, but somebody dropped the ball at centcom in not being aggressive enough. now, this is going to require clearing, which is going to take some time. further, mine-cleaning ships are not exactly military vessels, and they would be vulnerable to terrorist attacks.
this doesn't change any balance of power, it just creates annoyances and slows things down. it's a demonstration of incompetence by centcom that they let the inferior iranians mine the straits they have naval dominance over, right under their noses. it's an annoyance that's going to cost time and money to address.
that means that demining will have to wait, and there's no really easy way to make the straits usable again in the short run, even if they can send marines in to control the straits, which they should be doing.
i actually think they should do the opposite - they should blockade it and even mine the opening themselves, to prevent anything from getting in and out. demining will legitimately need to wait until moogabooga is eliminated and replaced with a democratically elected leader and iran will need to suffer the consequences of shitting in it's own bed.