From the 1600s to immediately after WW2, Battleship meant roughly the same thing, not "fast armored ship with big guns", but literally "Ship fit to stand in the line of battle". So yeah it's not a WW2 fast heavily armed and armored Iowa class, but those are obsolete, so we should be happy.

If the guided missile cruiser is now the biggest meanest surface unit, I'm fine with calling it a battleship.

Also, if gun caliber and armor plate thickness and speed, etc are less than the Iowa class battleship, the above still stands. It just means that the state of the art in what the biggest baddest ship is has moved on.

The aircraft carrier in many ways already became the new battleship in 1942, and existing battleships became effectively second rate in the sense that a fleet aircraft carrier smokes a battleship, it still does.

Another way to think about it is that guided missile cruisers are kind of another evolution of the aircraft carrier, they launch large numbers of missiles at much less cost.

Of course, the reality is much more complicated. It's unclear how useful guided missile classes and nuclear powered aircraft carriers will be in a standup full blown major power fight, aircraft carriers have sure been nice for asymmetric warfare in relative peacetime.