Wasp is a classic example why many USN ships don't work for the RAN.From my limited understanding, once they get to a certant size of function internal space will become waste and use still have the cost of moving a heavy hull through te water at additional cost for no gain, from what I gather the very reason why they chooses Canberra and not Wasp LHD
Man power - Classic Wasp is hugely manpower intensive. over 1000 sailors. this goes with their general doctrine and CONOPs. Damage control, watches, supervision, maintenance etc. The US has the man power for big intensive crews and they use them.
Steam Turbines(!). - Not only do they chew through fuel, they are also maintenance heavy and supervision heavy. The last of the Wasps was Makin Island with gas turbines and diesel generators. It apparently used a 1/3 of the fuel of a traditional Wasp most of the time.
The individual unit is just massive. It takes two LHD's to recreate one Wasp, but because of maintenance etc we would still need at least two.
The actual cost of additional friction with the water and the additional mass of the steel is actually fairly low in outright terms. If you were to shrink a Wasp class down 50-75% it would still cost a small fortune to run and would not be highly suitable for the RAN.
I remember after Timor, Australia was all over Wasp ships. Ministers, uniforms, aircraft. But it was instantly clear a Wasp class wasn't a good fit for the RAN. Like it wasn't when HMS invincible evaporated back to the UK.
Luckily the Spanish PDA/SPS which became JC1 was just coming off the drawing boards, pretty much perfectly fitting the needs of a middle power. With much lower crewing requirements but very capable size. Two deployed make a very good approximate of a one american LHD. Still, the crewing of two JC1 is less than the crewing of one Wasp LHD.
There are of course limits, scaling up designs can be problematic. Collins is a good example of some of those issues (but in a more complicated form).