I see where you're coming from, but don't forget that we are talking about beginners here. To them, everything is "hard to achieve". So when you tell them that, they just think "oh, no problem then, I will work hard, let's do this" and end up going in the wrong direction. And building a game engine* is the wrong direction for a beginner.

* where "a game engine" is a general-purpose set of tools used to build video games

If someone never laid bricks before, building a house is "hard to achieve". So is building a skyscraper... on the Moon. One of those things really should be called "impossible" for their own good