The source you cite says that people who've visited the named countries "on or after March 1, 2011" are ineligible. It does not say "in the five years before appplication."
It therefore appears that the ban is permanent, at least until some possible future change in the rules.
The same phrase, "on or after March 1, 2011," appears in the statute, at 8 USC 1187.
If you get a new passport without an Iranian visa in it, it does not change the fact that you were in Iran. If you apply for ESTA and claim not to have been in Iran, you risk being discovered and, likely, banned from the US for deception. Is saving the $160 and the interview for a B-2 visa application worth that risk?