Let me state that when players quit BFA early on many said there wasn’t much to do outside of raids, mythic +, or unrated/rated PVP.
It is more accurate to say there wasn’t much to do outside of instanced content in BFA that is worth while as a reward, and as a time investment . This is due to how punishing ground mount travel is in BFA zones, and flying heavily restricted.
AP in BFA is time gated by rotating world quests and those world quests are hard to navigate via the ground so you are forced to use the antiquated flight master system. Only time I would ever utilize the flight master system is when I am done questing. But the use of the flight master system going from quest to quest is very tedious and puts you out of the feel to play the game.
A hearthstone does something similar but at least it is a travel system that directly takes you where you want to go versus watching you go AFK on a flight path. The flight whistle is also designed in a similar way but again it is not good enough to help you navigate a zone for example if you goal is go for all the AP you can find.
Why navigate the world on the ground when AP is better doing island expeditions? Blizzard designed it this way and to reward players for navigating the world on the ground the rewards must be appropriate for the time investment. But that is not the case with BFA.
Gold rewards from world quests early in BFA were inferior than Legion because of two reasons. First because of the travel time associated and also due to the gold rewards not scaling for difficulty or time invested versus legion counter part gold quests.
Players quickly figured out that doing legion gold quests was better gold/hr than BFA gold quests via the ground/flight whistle. Even when the legion gold quests were nerfed, players figured I can do old content that I can fly to or even port to versus doing content on the ground and waiting for flight master whistle.
Crafting also takes a big hit. Why craft the new bags when I can go craft imbued silkweave or hexweave bags?
The time investment is greater to craft the same bags in BFA versus previous expansions. How does this make sense?
Why slog through the ground when I can save time. With that saved time I can actually play my alts, play another game or even go do some yard work outside.
If I can save time while still enjoying the game why not?
BFA is a failure of design in many ways and the gating of flying just points it all out like a sore thumb.