Interception comes with risks - the debris from that missile has to land somewhere. The only person confirmed to have been killed in the recent Iranian attack was a man in the West Bank who was crushed by part of a destroyed missile. It's clear that at least some of the missiles that got through were deliberately ignored because they were on target to hit open ground.
The best analysis I've seen is this Washington Post analysis that said that +24 Iranian missiles hit Israeli military/intelligence targets or were close misses:
I would say that's a pretty incredible intercept ratio.
We don't know if they were let through because their predicted targets or because there weren't enough interceptors or some other reason.
Air bases are pretty hardened targets. Most important stuff is kept in bunkers. They're also huge. The design assumption of an air base is that it's the prime target for rocket/missile/air raid attacks (and Israel airbases have been attacked by rockets in past wars, e.g. in the Yom Kippur war).
I've seen someone review satellite photos from Nevatim that seemed to indicate one or two hits to some structure. As far as we know nothing of value was hit and no one was hurt.
All that said, I wouldn't want to be around when these volleys of ICBMs are fired at you. Definitely not fun. But not a war winner either as long as they're conventional warheads.
