I agree with this. Like, yeah, there's all these different elements you need to bring a human character to life, but honestly? If you're not putting love into your environments to bring the environment to life outside of just, understanding how perspective works, then you haven't quite mastered them, I think.
When you know how to draw in perspective, that's great! You know the basic building blocks, just like learning the basics of anatomy. But the most important part of environments in my experience are the imperfections. Make it feel lived in, or aged; real telephone poles don't line up exactly, real brick walls aren't perfectly straight, real sidewalks have dandelions and cracks. Real rooms have furniture that's not even, stuff on the tables, on the chairs, on the floor. Real buildings have unique details and furniture that will be wildly different depending on the space. You're building the personality of a city when you decide what buildings go there; and the choices you make are gonna be a big part of leading the eye and setting the mood.
I think the idea that characters are complicated because they have gesture and different proportions, while environments are easier because you can just follow the grid and call it a day, does kinda a huge disservice to how much potential environments have.
That said, there are some artists who legitimately gravitate towards architecture as a strength, and the way perspective works seems to click with them very quickly or very early on. That's not any different from the way some folks seem to have a real sense of motion or other folks seem to have a remarkably natural eye for colour, and it's not something that's necessarily true across the board.
But ultimately, in most cases, "environments are easier than humans" is a moot point because humans often need to be part of those environments! Unless you're illustrating a car commercial, you gotta be able to draw rooms with people in them, sidewalks with people on them, cities with people all over them, participating in those environments in a way that makes them feel real. There's a reason I try to think of them as "environments" rather than "backgrounds" -- I think it's easy to fall into the trap of thinking of anything that's not a character as a backdrop, which makes it harder to feel like the characters are really populating that space and living in it.
Which isn't to say all this is necessary -- you can absolutely just draw a couch and a lamp and a line in the background to imply the floor and call it a day. You don't have to draw good anatomy or humans with different proportions, either. But both humans and environments have so much potential to show so much character, I feel like I could spend years mastering either and still have more to learn.