Well, programming has gotten more and more complex with so many different options. I don’t think imposter syndrome would be as much of an issue if apprenticeships were a thing (in the US). Obviously, people will feel they don’t know enough for a long time, maybe their whole career, but at the entry-level it’s a major issue because there are very few entry positions available for people to get started.
You basically have internships mostly only available to college students and are very limited in what you are allowed to do and how long you can do it for and then a few junior positions here and there but almost all of those require at least 2 years of experience. The result right now is a massive amount of talented entry level developers that can’t get their foot in the door (in the US) while we see every company has a ton of “senior” positions they can’t fill.
They would have plenty of senior developers 5 years down the road if more companies offered apprentice, true entry level positions.