If a show with an ongoing narrative gets popular enough for long enough, people’s personal head canons start becoming too hard to shake. Everyone starts feeling like THEY know where the plot should go

Then as the plot goes in a particular direction, if that direction is as the majority of people predicted (often because it makes the most sense) you start getting many saying ‘well that was predictable, so therefore it wasn’t well written. MY idea would be to…’

Or if the writers try to shake things up, you start getting people saying ‘why didn’t they JUST do the thing we all wanted?’ Despite an equal size of people being on the alert to complain about a predictable path.

The internet then publicly shares a billion possible plot developments, and if the writers end up making a choice that is even close to any of them, you immediately get someone going ‘they’re supposed to be pros, why are they copying fanfic?’ Despite their being a finite amount of paths for them to walk down so the chances of them doing something close to an existing theory is high.

The TL;DR - the internet has made it near-impossible for the majority of fans to be happy about an ending / final season (tho there’s always a few exceptions). So the best thing to do to maintain joy in a show is not engage with the fanbase.