Most workloads on FreeBSD are run in Jails. So that is very much "containers". Albeit a full system container. Heck even the older Solaris Zones or AIX LPARs have always been with us as containers, it certainly isn't new tech.
Also, the vote was "50% would believe containers would kill VMs". This is not the same thing as "50% are running VMs". This is already factored in. It is suggesting that 50% of people have seen such an uptake of containers vs VMs that they believe VMs to be an obsolete technology. Possibly they have seen 5% VM vs 95% containers for example.