Iran's political and economic collapse seems gradual but could it shift to sudden?

Eight years after Iran’s Green Movement and antigovernment protests, will the current unrest in the nation have no lasting impact or is it the beginning of the end for the repressive theocracy? Abbas Milani, a Hoover research fellow has made the case that Iran could be on the brink
Ernest Hemingway said ‘How did you go bankrupt? Two ways. Gradually, then suddenly.’
Iran is strategically weak because it faces daunting challenges — from oil price changes and water shortages to a disgruntled, Internet-savvy, youthful population, led by increasingly assertive women, hampered by chronic double-digit inflation and unemployment, and angered by corruption, cronyism and the squandering of massive sums in proxy wars, particularly in Syria.

John Bolton, Donald Trump’s new national-security adviser, has long advocated regime change in Iran, and more recently has argued that the administration should openly embrace it as a foreign-policy goal.
Most are expecting Trump will pull out of the Iran nuclear deal and re-impose sanctions.
The thinking is that with Iran regime and economy already weak that more pressure could cause a collapse.