You wouldn't believe how many people on these forums told me that "The Spark already has a successor, it's called the Mavic Air"...
To be honest, the Spark was marketed as a selfie drone that could do all by itself, with many automated flight modes and relatively sophisticated sensors (both obstacle avoidance and gesture control). The fact that it opened a whole new customer base that actually uses the Spark as an entry level Mavic was not anticipated by DJI I think.
So where does that leave the Spark? Does DJI feel there is still room for product diversification between a compact entry level drone with advanced autoflight abilities and a compact entry level drone for without those abilities? Noone knows, and I think that is what the big confusion is about...
The way I see it, you could introduce an absolute beginners drone like the Tello, which is basically a toy. Then there could be a diversification between people who need advanced selfie abilities and people who don't need all the sensors but want a better camera platform, and above that the Mavic Zoom/Pro.
Does this leave room for a Spark 2? I don't know, only time will tell I guess...