It’s very distracting now to scroll down to place where you left off, especially when you switching (Command+O) between large docs. Also would be helpful to sync it between different client (desktop and mobile e.g.).
I remember we have tried this before, and it caused some issues so we reverted it.
Namely, because unlike a Word or Google Docs document, as you collapse things, the scroll position might stop making sense.
And how long this scroll position should be valid for is another problem. When you have forgotten about the last time you edit it, auto-scrolling to a position can be annoying rather than helpful.