IRBMs weren't the problem. The launches tapered off fast - either due to munition depletion and supply disruption, attrition of launchers and munitions, or efforts to conceal the launchers in face of persistent airstrikes. Either way, the threat was suppressed.

By all accounts, US is much better at "Scud hunt" now than it was back during the last attempt at it.

One-way attack drones? That's a new threat, and one US is far less equipped to tackle.

But I don't think that "OWA threat" was where US strategic planning has failed. From the outside, it seems like US plan was to make a single decisive strike, and negotiate with cowed Iran from there. Iran has failed to be cowed by a single decisive strike, and there was no workable Plan B for forcing it to submit if it didn't. That's the key strategic failing. Persistent OWA threat is downstream from that.