A large percentage of those hosts with SSH enabled are cloud machines because it’s standard for cloud machines to be only accessible by SSH by default. I’ve never seen a serious security guide that says to set up a VPN and move SSH behind the VPN, although some cloud instances are inherently like this because they’re on a virtual private network managed by the hosting provider for other reasons.

SSH is much simpler and more universal than a VPN. You can often use SSH port forwarding to access services without configuring a VPN. Recommending everyone to set up a VPN for everything makes networking and remote access much more complicated for new users.