Construction companies can do all sorts of projects, and still usually have to meet a deadline. Do you think every bridge or skyscraper is the same, just because they are all bridges and skyscrapers? And do you think mechanical engineers are also not estimating delivery dates just because they usually create new stuff? Because that's not the case.

Also, tons of software dev isn't actually about pushing boundaries or doing something that hasn't been done before. In fact, I'd say most development is about implementing known solutions but in a customized way. Just like every other engineering field.