The real question is, can you level up to 50 without chromie time in any expansion? you mentioned doing it in Legion content, but I’m not surprised by that at all, since it stops at 45… that’s practically level 50 anyway.
I’m already level 32 in Draenor, and all I did was the first zone. I can only assume I’ll be level 50 by the end of the second zone… but what about Pandaria? or the level 30 zones? Northrend, Outlands, Eastern Kingdoms and Kalimdor?.. actually, those areas have so many zones and quests that I wouldn’t be surprised if you actually could make it to 50 in all of them… maybe not Outland? that one I recall not taking as long as Northrend…
Edit: Quick! someone level through Outland without Chromie Time to find out! xD