We could definitely do more - one of the challenges here is that some bacteria are quite picky about where they grow - ie there a lots that don't grow on a petri dish. So not always so easy to grow side by side.
Note from the paper - they stored the soil samples for a year on growth media before testing ( to allow any compunds to build up presumably ). That doesn't sound like a fast process.
Our knowledge of what's out there is quite biased by what grows well in the lab - probably less than 1% of all bacteria will grow on an agar plate.
The question is shouldn't we explore it more?
Put dangerous bacteria in contact with other bacteria, fungi, viruses, prisons, viroids, archaea and see what kill them, how and why?