Yeah, but you can always buy a slightly smaller bird, strap the warhead directly to it, and fly that into your target 100+ miles away.

Guided missiles specifically are insanely pricey by comparison to the warhead alone; just for the possibility that your slow, vulnerable drone might be able to return (and be used again) you have to make very expensive engineering tradeoffs, and even when the thing comes back you have to repair and service it, too (and stock it up with more expensive missiles).