You made a personal assumption (the part where you said that non - 2/2/2 game modes will somehow, someday replace today’s default game modes) based on an observation you made about the game.
The observation part, as long as it’s made in a report - like manner, is objective. The assumption you made though is nothing more than a personal opinion of yours.
I for example certainly acknowledge the observations you made. But, for me they mean that the dev team someday decided after discussions that the game modes in question were popular enough according to them in order to guarantee them a place in the main menu and/or they were implemented in order to help with the queue time problem. That’s it.
Okay so actually definition - wise the word assumption means that you’re totally sure that something will happen according to you, while the word speculation means that there’s just a possibility of said thing happening, again according to your own crisis.
So yeah the word speculation is the correct one to use here, actually.