There probably are an awful lot of them. Of all the bacteria that exist in the world (detectable by genomic methods) only a tiny fraction can be isolated and grown on their own. [1][2]
In many cases it might be that we just don't know how to provide the right environment, but part of it is that many bacteria only grow together with partner bacteria of other species [3] [4] For that matter, there are many bacteria that have lifestyles based around living on biofilms created by conspecifics. [5]
In many cases it might be that we just don't know how to provide the right environment, but part of it is that many bacteria only grow together with partner bacteria of other species [3] [4] For that matter, there are many bacteria that have lifestyles based around living on biofilms created by conspecifics. [5]
[1] Like dark matter
[2] https://www.worldwidejournals.com/international-journal-of-s...
[3] https://ecampusontario.pressbooks.pub/microbio/chapter/10-2-...
[4] https://teamaquafix.com/sulfide-reducing-bacteria/?form=MG0A...
[5] https://en.wikipedia.org/wiki/Biofilm