Hm? IIRC, the numbers that we have today is much higher than when I first discovered Bitcoin (in the range of 7-9k) and Bitnodes was running a campaign to encourage people to run full nodes. The only problem is that there is far higher proportions of nodes on datacenter ASNs than before.
Although it's true the number is far lower from decade ago.
May I know the statistic for this?
Unfortunately i couldn't find data or discussion about node count from about decade ago. But according to Luke's data[1], on 2018 there was peak ~205K total node count and ~23K total listening node count.
[1]
http://luke.dashjr.org/programs/bitcoin/files/charts/historical-dygraph.html