I can get behind this, especially given that it IS fully possible to make a gamerule for it.
Yeah, I assume the reason they haven't added one is because they're planning on redoing the combat for 1.15 anyways, so adding a gamerule that's probably not gonna exist for much longer would be counterproductive. It sucks, but it's understandably why they wouldn't do it. I think that's also why they haven't added the 1.9 combat to Bedrock.
If we come to this forum I think we all enjoy the game! Maybe it doesn't have the same appeal as it did when the game was new but man oh man I have never enjoyed a game for this amount of time before! Minecraft forever and ever <3