I have argued the same- that the, perhaps unintentional, mantra of the Union navy was similar to that of the English vs the French navies. The French, under-powered & under-funded, looked for new tech (think iron-clads, rifled guns, shell projectiles, submersibles, etc.) to dispose of the English, but the cunning English simply out-built the French after a technology was proven (a term I use lightly), forcing them to turn to even newer weapons.
Likewise, the South was the first to embrace iron-clad technology but they could not produce enough quickly and were soon outnumbered in that realm. In response, they looked for a new weapon. That was the torpedo- to attack at the vulnerable wooden hull of the iron-clad below the waterline. Inexpensive and (theoretically) effective.
At first there were defensive static torpedoes, then they moved to offensive torpedo boats. Blah blah blah, the point being that the South, after Virginia vs Monitor, apparently saw the futility of the iron-clad as an offensive weapon (Beauregard certainly did as evidenced by his letter to Mallory about the ineffectiveness of iron-clads) and never really embraced the iron-clad in that manner, but in a defensive one.
Even in Charleston, which never fell by sea, the Confederate iron-clads were pretty ineffective. It was the heavy fortifications and natural design of the harbor (along with the poor gun inclination capabilities of the Union iron-clads) that kept the Union navy at bay.
IMO, in hindsight, we can say the Confederate iron-clads were essentially a waste of money, but at the time it seemed the way of the future, and to a certain extent that was true, as ironclads morphed to iron ships that morphed to steel hulled vessels.