I’ve had an iPad since 2010. I usually upgrade to the latest.
You are correct, it’s possible to do all those things on an iPad. But as someone who’s attempted to use the iPad for work — I even have the shitty iPad keyboard Apple sells — it takes me more time and effort to do writing tasks (and many other tasks) on an iPad than on a regular mouse/keyboard interface. Even something as simple as managing a Linux server via SSH is difficult. The iPad keyboard has no ESC key. Many remote access apps, e.g. Prompt, include it as an extra on the on-screen keyboard. However, the on-screen keyboard is hidden if using a hardware keyboard so the user spends time tapping the screen to bring up/and remove a special commands keyboard.
Google “iOS ESC Key“.
There are other limitations.
So while I love my iPad, I freely admit that it’s an inefficient tool for many tasks and some tasks are impossible on the iPad.
I can cut my lawn with scissors. It’s doable. I am sure someone somewhere has done that. But a scissor is not the best, most efficient tools to use to cut a lawn. For that, we have lawnmowers.