You’re a bit too focused on repeating argument “employees wandering through millions of lines of source code”. It’s invalid since nobody needs to know the entire engine. At the same time blueprints (or any other scripting language) it’s also the way of “wandering through the entire engine”, thousands of methods exposed. Still, nobody needs to know it all.
Understanding the engine by reading its source code it’s not “wasting time wandering thru millions of lines of source code”. It’s making most of the engine. Especially when someone is writing functionality which it isn’t available already - in the engine or any Marketplace plugin. You writing something new code, you have to be ready to understand underlying software, hardware and problem to solve… There will be never documentation on everything you need.
But do they document code for every single feature and Apple app available? I ask since Unreal C++ syntax/core changes slowly and there are no many changes. The community would use a proper explanation of core Unreal programming concepts. I totally agree with this part.
Although comparing documentation Swift API with documentation of engine features is a bit off. It’s impossible and pointless to document the ever-changing engine, the source code is the best documentation.
Epic does slowly work on the online course, explaining some things in live streams. It’s far from ideal, but the official docs it’s the only learning resource.
There’s an amazing amount of knowledge and help provided by the community. You can ask about the engine on Reddit on Unreal Slackers and often receive a proper explanation. No need to be this glorified “huge software house”. The hobbyist will get there the same as “AAA engineer” if the question was properly phrased.
Obviously, companies with bigger employee count always have an advantage while working with huge software/mechanism. Not only in IT