It'd be interesting to see if the decrease was comparable to pre 3.3 levels, a decay in activity is somewhat expected between long periods of updates*.
Not really. The largest drop between two months was 2019 May to June, -602,656 systems. The second largest was 2017 Oct to Nov, -361,181 systems. However, the difference there is that from 2017 Sept to Oct, there was a big spike of +453,880 systems, while 2019 Feb to May was mostly the same. Otherwise, for the full year before the FSS, months would see gains or losses in a 50-150k range.
That +453,880 spike was the third largest. The second largest was at the launch of Chapter Four, doing +549,918 in 2018 Dec, and the largest was +861,746 in 2019 Jan, at the launch of DW2. Both were however in the middle of their respective months.
It is an interesting argument to say that decreases in exploration activity might come from players having already explored some routes, but there are some problems with that.
One: those decreases
and also increases are too large for that.
Two: DW2 flew along quite well-established routes anyway, and still produced a whole lot of unexplored systems. If Qohen Leth's figure of 50,844,000 new planets and stars by DW2 is correct (I can't verify this without a lot of work, unfortunately, but I trust it is), then that was a whopping 76% of the 66,508,000 new planets and stars uploaded to EDSM during the expedition's time.
Three: does this say anything about why people are scanning now half as many new bodies per system as they did before, and less ELWs per system even?
Lastly, there is something interesting and relevant noted elsewhere. Check out the
EDSM traffic reports,
decaying heatmaps, the
Commanders map (you need to zoom in a bit): there are actually not a lot of explorers who don't travel between known destinations, but set out into the deep galaxy instead. You could even count them manually on the videos. Most of exploration is people flying to and from Sol - Colonia - Sagittarius A* - Beagle Point, to a lesser extent.
Personally, I'm not really happy about this, but it is what it is.
Oh yeah, one final note:
Don't worry, I'm exploring without using the FSS, so I'm completely messing up
@marx's stats.
Hehe, good thought. Unfortunately for you, the automatic scanning logs things the exact same way as the FSS does.