"and we all know what happens to countries that are destroyed but not rebuilt..."
No. Please tell me.
you may remember a place called afghanistan, no effective central government, total international disinterest.
look what based itself there, look what took power because no other force was able to resist it.
if you remove irans government - its instruments of state power - you need to replace them with something else. that needs occupation - and iran is twice the size of iraq with three times the population. moreover you won't be able to move seemlessly from iraq to iran, any civil disorder in iran will spill into the southern shia areas of iraq very quickly.
so, limited airstrikes aimed at removing irans nuclear capablity are ok, but widescale airstrikes aimed at removing the iranian government from power without a viable replacement being available are a disaster waiting to happen.
if iraq uccupies some 100,000 us troops with a friendly north and a fairly benign south you may have fun finding troops to handle all of iran as well.