The processes in manufacturing largely remained the same. Doing things faster makes things easier not more difficult.

Look at the Eiffel tower for example, immensely complicated, wild design and largely pointless (compared to modern standards).

Or compare old wooden windmills to one of the most modern structures, large open water windmills. hundreds of meters tall, simple tubular construction.

The ability that CAD and computer power in general gave us was the ability to simplify and not use more than necessary. The ability to model strength, rigidity and whatever forces necessary, that’s where the real power lies.

and i think that we can’t really speak about more or less difficult. The structures and designs clearly have a very high level of complexity, while most modern constructions deliberately eliminate complexity. But we can’t do that without computers.