I thought the general consensus in the Intelligence Community was that after Natanz, Iran spread nuke facilities amongst too many smaller sites that are buried too deep for most conventional weapons - that’s why an aerial strike didn’t make sense anymore

https://www.i24news.tv/en/news/international/artc-iaea-s-grossi-iran-s-nuclear-installations-are-too-deep-underground-to-be-destroyed-by-surgical-strike