A battle ship is a weapon system. An amphibious landing is a tactic.
The battleship became outmoded by cruise missiles and naval aircraft from aircraft carriers. Capability is still needed we just choose to do it differently (better, more efficiently).
You're confusing capabilities and tactics, or rather you're arguing both sides.
Yes, a battleship is a weapon. But naval gunfire is a tactic. The inaccuracy of the tactic and the vulnerability of the battleship made the tactic and weapon obsolete. Is the capability to conduct indirect fire on land-based targets still around? Very much so. Is the battleship the modern method? No.
Is a dynamic entry into a hostile country still needed? Yes. Just like Battleships, amphibious landings and the weapon systems designed for them, have become outmoded.
We have much faster and powerful methods of forced entry now than having a flotilla of AMTRACKs and LCACs assaulting a defended beach. That's not to say we won't practice the hell out of it, but we also practice the spirit of the bayonet.
That's not to say an amphib capability is worthless, it's just something that doesn't make sense to do in an opposed fashion anymore. We don't need to take beaches now. We conduct resupply and movement onto uncontested shores.
I suppose if WWIII kicks off, we might get desperate and use. But for now, amphib assault is a footnote capability. Just like parachuting and rappelling en masse from helicopters.
Note: ship-to-shore ops and amphibious landings are not one in the same for the purposes of this debate.
Anyhow, we should probably let this thread get back on topic.