I think it would be convenient if binary packages of Foxy where available for Ubuntu 18.04. Most platforms haven’t moved on to Ubuntu 20 yet but Foxy contains many useful features and bug fixes it is a shame it is not available.
Please see REP 2000 which mentions (briefly) why we never target more than one Ubuntu LTS with the same ROS distro.
That being said you can try to build Foxy from source on Ubuntu 18.04.
Note that the Foxy Docker images are available: Announcing ROS Foxy docker images availability .
(Shameless plug) - Similarly you can use LXD containers: Get started with ROS 2 Foxy today with LXD.
I have successfully built Foxy from source on my 18.04 machine. That was very shortly before it was officially released (so, actually, all I was building was master), but I would imagine that it should still work.
Ok, I understand. Using docker images in production is the best option anyways.