That would be because the formatting required for writing content for NewLife is intensely infuriating and requires the comprehension of code. A simple paragraph often requires over a page of text and code. Let alone writing a series of events with choices, responses based on traits of the PC and people in the scene etc etc.
If writing for NewLife was easy- there would be a ton of content for it and the dev would likely have a ton more content produced.
I wrote a scene, and started with literally zero coding knowledge.
Yeah, it's code, but it's also pretty simple. For the most part the logic is fairly straightforward, and there's tools out there that make it way easier.
It's also a bunch of work. You're right about a simple paragraph requiring over a page of text and code, but that's because you're writing for a game where you can have all sorts of variation. That's not because the structure is bad, that's because you need to adapt to multiple different possibilities.
The work in writing a scene for Newlife is because the game isn't on rails, and because there is the possibility for a ton of variation. It's not hard, it just requires that you actually put in some time.
I'm not sure what sort of "easier" you want here. Writing a corresponding scene in anything else is much harder, especially because you can do things in Newlife like go to the pre-written sex scenes.
But, you're right that it's code. Newlife was actually the training wheels that got me going enough to be able to start a project of my own in Sugarcube. I've had to learn a ton of additional stuff, but was really glad for the skills developed.