I don't think WotC wants to change the default rules on length of Short Rest because they recognize that is one of the easiest things for individual DMs to houserule. So easy in fact that they give us all suggestions on how to houserule rests in the DMG.
If they are flat-out telling us to houserule rests if we feel we need it... then it doesn't matter what the base rules are. And if they have determined that the "hardline" play groups that find Wizards and Clerics are dominating the game and Warlocks and Monks are getting blown out of the water because they don't short rest are a rare sub-group of D&D tables... then WotC obviously will not use those tables as evidence that the baseline rest needs to change.
I do 10-minute short rests and leave long rests as 8 hours. And literally nothing has broken the game by doing so. So what difference does it make that I'm not using the "official" rule on short rests? There is none. The only people for whom playing "official" is required and it might possibly affect are those players who are stuck just playing Adventurer's League as their only option and finding their AL DMs run games in such a way that the player CAN'T play a Warlock or Monk because they get shafted by that DM's playstyle and the 1-hour short rest. But at that point those people are such a small minority in the overall D&D population that WotC just seems reticent to change rules just to make certain small group of players lives easier when they don't impact the larger number of the playerbase. Especially now that playing "Official AL" has taken such a backseat to how the game is played and run. Even when I go to cons and play Adventurer's League, the games all seem pretty wishy-washy nowadays about worrying about officiality and keeping track of the quests you go on and the XP you earn, and Renown, and Factions, and the whole "magic item economy" in AL etc. It's nowhere near as stringent as it was 9 years ago when AL first started.
If they are flat-out telling us to houserule rests if we feel we need it... then it doesn't matter what the base rules are. And if they have determined that the "hardline" play groups that find Wizards and Clerics are dominating the game and Warlocks and Monks are getting blown out of the water because they don't short rest are a rare sub-group of D&D tables... then WotC obviously will not use those tables as evidence that the baseline rest needs to change.
I do 10-minute short rests and leave long rests as 8 hours. And literally nothing has broken the game by doing so. So what difference does it make that I'm not using the "official" rule on short rests? There is none. The only people for whom playing "official" is required and it might possibly affect are those players who are stuck just playing Adventurer's League as their only option and finding their AL DMs run games in such a way that the player CAN'T play a Warlock or Monk because they get shafted by that DM's playstyle and the 1-hour short rest. But at that point those people are such a small minority in the overall D&D population that WotC just seems reticent to change rules just to make certain small group of players lives easier when they don't impact the larger number of the playerbase. Especially now that playing "Official AL" has taken such a backseat to how the game is played and run. Even when I go to cons and play Adventurer's League, the games all seem pretty wishy-washy nowadays about worrying about officiality and keeping track of the quests you go on and the XP you earn, and Renown, and Factions, and the whole "magic item economy" in AL etc. It's nowhere near as stringent as it was 9 years ago when AL first started.