It has cost Iran nothing thus far with respect to its relations with the wider world. Why would they change what they've been doing?

Since the UNSC can't even get its act together for a force for Lebanon, Iran's government probably sees no possibility of serious consequences in continuing it's present course. One can't blame them for apparently having that view.

I fear that we (the West) are merely delaying a confrontation until the conseqences will be even more dire.

:-(

Cheers,
Scott.