This might be a silly question but I am genuinely curious why they don't do it. I feel like the title is a little bit vague so let me put it this way:

For example; if you start your project with the first person template, you automatically have a basic, premade but functional shooting system. And you can tweak it, build upon it according to your taste. Another example would be, walking system is already premade so by tweaking some settings in the blueprints window, you can implement a sprinting function pretty quickly. One more example would be jumping. Such basic Interactions are already provided by Epic. I hope these examples get my curiosity across.

So my question is, why doesn't Epic expand the library of these pre-built functions? They could add some other generic stuff like picking up an object, opening/closing doors, static/dynamic weather conditions, reloading system or maybe even more complex features like party member functions as in most RPGs where you can switch between the party characters, etc.

If the concern is that a lot of people could start using these systems without making any adjustments to them, and as a result we could get thousands of low effort games, we already have those type of games in every marketplace.

It also appears to be like a lot of people with no prior coding experience follow YouTube tutorials about the feature that they want to implement in their game and build upon those features anyway. We also have websites where people share the screenshots of their functions so you can take a look at them and learn how they implemented a feature. My opinion is that by having such premade functions, it could grab beginners' attentions more and make it easier and more exciting for beginners to learn about how C actually works under the hood through the blueprint system.

I am aware of Epic wanting more indie developers to use their engine and I read that providing UE users free access to Megascan assets is one of the steps that they took to make this a reality. Do you guys think that spending your resources on such project would be a waste of money considering that Epic only gets its share after a minimum of (I guess it was 1 million the last time I checked) revenue criteria met?

I used to be a web developer so I'm very well aware of every project might need very specific features for them and that's not what I'm expecting Epic to implement or provide. Think of my questions as those big JavaScript libraries such as React, Angular, or Vue, where there's an already made, tested and established template is provided to programmers and newcomers. And by using the template and the features come with it, you can prototype a project very fast. I believe it's already pretty fast prototyping stuff with the blueprint system and with the help of such pre-built functions, it could make things even faster. I am aware of there are a lot of valuable informations on UE Portal about the engine and it's capabilities. I'm just genuinely curious why we don't have a simple functions library.