The Navy also had a greater mass & volume to play with for such a system.
While ground forces want something for NGS- Naval Gunfire Support- it is not something surface commanders want. The Fighter Mafia is not a new thing in armed forces, admirals have played that game for a long time (Steam? A fad I tell you, give me a reliable sail any day where I do not have to worry about some contraption breaking down without a way to fix it.) which is why subs were slow to be adopted and even if we tested the carrier concept first it was up to another navy to actually implement it. The Admirals do not want a ship loitering for NGS, not their 'job' . . . IF it had been something the Navy was even throwing a bit of support at we could have had destroyers or old fashioned cruisers using 155mm and MLRS along with some AA/ASW capabilities long before. But it is not something the institution is interested in- see how quickly the BBs were retired again w/o a replacement after the Soviets fell and Reagan's Navy hull target was no longer a priority.
gotta be fair there, Colt, you're right about the various 'mafias' in the various branches, but as for the Iowa class, it was a matter of operating costs versus capabilities (including the question of how often you NEED those capabilities, which hasn't been that often since the early 1990s.)
there have been proposals for 'Arsenal ships' for naval fire-support pointed inland, but in general practice, we haven't faced a peer level threat that also has a large coastline in a long time. (Afghanistan was entirely inland, Iraq's coast is short, most of the country's deep inland, everywhere else since the 1990s has been either third world or inland...)
This isn't to say there isn't a gap-there is, it's massive...but...the conflicts post GW-1 haven't been the kind that see either a lot of amphibious landings, or coastal bombardment.
It's a bit like the old "Coast Artillery" problem-the technology to do it has languished in part because the need for it has been...scant, rare, hasn't happened in a while. Eventually something WILL change...