We can easily predict as unlike in 2015, Iran has a powerful (politically) ally in Russia.As I said…the Iranians would not be developing nukes now and would have been aggressively advancing their nuclear program since 2018 if Trump hadn’t pulled out of the deal. Iran would be further away from a bomb and the world would be far safer than it is now and that is because of Donald Trump.
What would have happened when the deal expired in 2016? Well…I guess we’ll never know.
As I said, the deal was better than nothing but it did not solve the problem and even during the deal, Iran was delaying and ignoring the IAEA. Not enough to cancel the deal IMO but it was a huge indicator that the issue remained.