They point out Iran took a harder economic hit during the eight-year war with Iraq in the 1980s, the Los Angeles Times reported.
"Iranian nuclear physics is beating out Western economics -- they're not yet feeling such severe pressure that they feel they have to compromise," said Mark Dubowitz, an energy specialist at the Foundation for the Defense of Democracies, which supports sanctions.
The middle-class is already feeling the pinch. Ali, a print shop employee who did not want his full name used, told the Times he has "downsized" his life by switching to Iranian cigarettes, convincing his wife to give up her health club and cutting back on meat.
"As time passes and dollars are lost, inevitably ordinary Iranians are going to ask the question, 'Is it worth it?' " said Cliff Kupchan, who moved from the U.S. State Department official to the Eurasia Group consulting firm.
New sanctions kick in this week, including an embargo by the United States and European Union on Iranian oil and a ban on insuring tankers carrying Iranian oil that would prevent them from getting insurance through Lloyds of London.