This sort of story regularly resurfaces (see what I did), much to many peoples amazement.
The truth is that concrete is NOT the simple cheap rubbish that people think that it is. It's actually as complicated as steel, but again people think that's something simple.
Start with the basics of concrete. You need to chemically reform calcium carbonate by a process of heating it to high temperatures and controlling the gases it's exposed to during the process. In Roman times this would have been done using firewood, probably chopped and lugged by slaves, in a carefully constructed kiln.
Cement it just part of the process in making concrete. Different "aggregates" have different properties. They can change the PH of the concrete to prevent rebar from rusting, cause it to become antibacterial, allow it to set underwater or change how dense it is. The Romans didn't even use the same concrete throughout the same structure. The concrete at the top of the partheon is not the same as at the foundations.
[quote][Different aggregates were used to give the concrete diverse densities. Travertine limestone gave the Pantheon’s foundations a density of 2,200kg per cubic metre, while lighter rock was chosen for the dome./quote]
As for skyscrapers, as far as I know they were/are never "made" of concrete. It simply doesn't work for the job once you get to any height, though it's ideal for the foundations.. Skyscrapers need to be relatively light and flex with the wind. The sway in the world trade center use to make some feel ill. They swayed up to 12" or 300mm on windy days.
It may be worth considering though that the complaint about skyscrapers, may be about a very different type of building, and aesthetic.
This book may be a insight into alternative views upon the use of concrete as a decorative substance.
https://www.amazon.co.uk/Lost-Futures-O ... th=1&psc=1Some great photos of buildings that no longer exist, because we don't like the appearance.