I don't think that it's actually true though. There are definitely areas where I don't have to make it up (anymore, at least). As a trivial example, implementing yet another API endpoint for a web form or something is not something where I have to experiment a lot (anymore).

It's also important to realize that in most fields, people are definitely not just making it up as they go along. A dentist or an airline pilot has extensive training, knows what they are doing and why. This is even true when it comes to estimation tasks.