If you’re thinking of trying to build your own app then sure it’s a very competitive market especially for games and I wouldn’t recommend it if your goal is to make money. However, mobile apps are very important for most tech companies as native apps are still the best way to deliver a mobile experience and are expected from users.
There’s a large demand for mobile developers in my area (LA) where they frequently command higher salaries than similarly experienced web developers. I’ve seen this in other markets I’ve worked as well – there’s generally less mobile developers then web developers. If you care a lot about salary it might be a good way to give yourself a bump (check your local market for salaries of course).
That said, I’d say stick with web development if you’re still early in your career and you don’t actually care about which one you do. The mobile landscape has been changing pretty dramatically with cross-platform frameworks like React Native and Flutter in addition to PWAs. With a web developer, you get a more generalized foundation and can pick up mobile if you want later.
People have been saying that for at least 5 years straight. In my opinion, if the native is ever replaced, it will be by Flutter or something that closely resembles Flutter or Unity. Nobody is satisfied with the web experience on mobile. And also, nobody is particularly excited to develop in a legacy language such as JS.