“Logical” file systems aren’t necessarily mounted over the network; for example on your system with 70 mounted file systems, it’s likely most of those were file systems corresponding to kernel features rather than network file systems. Logical file systems include
proc, all the cgroup file systems,
devtmpfs, etc., which are all “local” file systems.
“Non-physical” file systems are identified by the kernel in
nodev, so you can use that to list “physical” file systems only, using
findmnt -t $(grep -v nodev /proc/filesystems | paste -sd, - | tr -d \\t)
To count the file systems, drop the header and feed the output to
findmnt -n -t $(grep -v nodev /proc/filesystems | paste -sd, - | tr -d \\t) | wc -l
It is possible to mount such file system types from image files and other non-device files, even remote block devices over the network; however this approach will give you good results on most systems.
Another approach is to start from the disk devices themselves, using
lsblk -f will output the tree of physical devices through however many layers are required to reach actual mounted file systems. You can combine that with the above information about physical file systems to list only file systems which match a block device on the system:
lsblk -f | grep -F -f <(grep -v nodev /proc/filesystems | tr -d \\t)
Counting that gives the desired result:
lsblk -f | grep -F -f <(grep -v nodev /proc/filesystems | tr -d \\t) | wc -l