Why everyone says web dev is simpler than mobile dev and what do you suggest to start from?

When you ask someone if, as a beginner, it's better to approach either mobile or web development, everyone answers that web dev is simpler. I'm not sure that nowadays it's still true: maybe 10 years ago, when there weren't lots of resources to learn android development, that was true, but now, with so many frameworks (such as Flutter, React...) that make things simpler, i think something changed: to become a web developer you have to know at least three languages for the front-end and, with todays requests, you probably should learn at least one back-end language. To become an android developer, instead, you should learn only one language (like Dart or JS) and, if necessary, a backend language (sure you can learn native Android or iOS, but today most of the time it's more productive to learn a framework). What would you suggest me, maybe to start a career in the future? Thanks in advance