You're right about what you said, but web designers and developers aren't usually to blame for this.
The problem isn't cultural traction among web designers and developers, but among the CEOs and marketing guys and VPs who, for egotistical or political reasons, order the designers to implement the site in a certain way.
They love carousels because, as you said, carousels feel like a design cheat code that let you fit 5 (or more) times the amount of content in the same amount of space. Instead of actually researching your niche and making a choice about what content is most important to solve your customers' problems and your own goals and what content gets priority on a page, they take the lazy way out and order the designer to fit everything on the screen.
Most decent web developers who place a premium on UX will not usually suggest a carousel as the best way to display some content on the screen, and they may fight those decisions as best as they can, but at the end of the day the people who pay the bills will make these decisions.
The problem isn't cultural traction among web designers and developers, but among the CEOs and marketing guys and VPs who, for egotistical or political reasons, order the designers to implement the site in a certain way.
They love carousels because, as you said, carousels feel like a design cheat code that let you fit 5 (or more) times the amount of content in the same amount of space. Instead of actually researching your niche and making a choice about what content is most important to solve your customers' problems and your own goals and what content gets priority on a page, they take the lazy way out and order the designer to fit everything on the screen.
Most decent web developers who place a premium on UX will not usually suggest a carousel as the best way to display some content on the screen, and they may fight those decisions as best as they can, but at the end of the day the people who pay the bills will make these decisions.