That’s theoretically true, but in practice, the desktop experience (screen size, interaction model, etc.) is sufficiently different that adapting it to mobile to get an app-like experience is not that different from building a separate app.
It’s not at all like building a separate app. All the back-end code is identical - all you have to do is make the mobile version not take up as much screen-space, and that’s not much work. e.g. on desktop I use icon and text, but on mobile icon only.
That’s theoretically true, but in practice, the desktop experience (screen size, interaction model, etc.) is sufficiently different that adapting it to mobile to get an app-like experience is not that different from building a separate app.
It’s not at all like building a separate app. All the back-end code is identical - all you have to do is make the mobile version not take up as much screen-space, and that’s not much work. e.g. on desktop I use icon and text, but on mobile icon only.