It just feels unnecessary. They're going to do a level 60 boost soon anyway, which means they'll have the mechanics set in the game for people to hit 60 and then get access to their Covenants, so why not let it happen earlier? If the idea of Chromie Time is "level how you want to" then they're just not meeting that bar with the current implementation, and some people are bothered by that and would like to be able to use Chromie Time for longer, possibly even at max level for fun.
60 boost is already in the game, it has been for a few months now.
If you don't like current Chromie it's up to you, but as any other previous expansion, you are forced to level in current expansion zones.
Also, Blizzard never mentioned when they announced Chromie that you would be able to level to 60. It was stated that you can use Chromie time to level through your selected time-line until you catch-up to current level, which was 50 when Shadowlands launched.
Timewalking is active every 3 weeks or so (might fluctuate, not at PC to check) which is a way to reach 60 without doing SL content.
Now, I think that TW should be available every week, and before reaching 50, but that is far from what the root comment of this thread asked for.
But your duty to Azeroth is not yet complete. More is demanded of you... a price the living cannot pay.
The truth is that it is extremely jarring to be pullled out of Chromie time for no other reason than you just hit 50, and they need a better system.