Well, actually there IS something the large ships could do to make embarkation less painfull. But it results in something the large ship lines do not want ---- spending more money. They could have more than one "front door" to the ship by alphabetical last names of the guests, and have more people manning the check in stations. I agree that security (so long as it is not just checking for carry on booze) is an important item. But it is one the lines should provide for, instead of putting it on the backs of the guests via longer lines.
Because of this (and other things) we do not cruise on large ships. In my opinion, they are not in compliance with the Americans With Disabilities Act, which has received very lax enforcement as to cruise lines when operating on American soil under the current administration. But, we can do little about this except to keep it in mind the next time we vote. In the meantime, my wife and I must avoid such messes, due to rather mild physical disabilities, and confine our cruising to small ship cruise lines. Heck, that is probably the best idea anyway. Never had to worry about a chair by the pool!