I have been looking around the internet finding articles that talk about what you should learn to develop a game engine. Something that I keep hearing in many articles is that you should learn low-level graphics API's such as OpenGL or D3D11 (great article for example: https://www.haroldserrano.com/blog/how-to-become-a-game-engine-developer) for graphics rendering for instance.
NOTE: I will be using graphics rendering as an example for my question since it makes the most sense to me here.
This got me thinking. Is it really necessary to re-invent the wheel by creating your own framework for just rendering graphics? Isn't it sufficient to learn a library like babylon.js for graphics rendering on the web? If the main goal of creating a game engine is to lay a software framework to build video games, then spending time on developing an entire framework for graphics shouldn't be an issue if others have solved the problem for you via their graphics libraries.