Academia is usually about minutiae, not concepts. Sometimes they get so hyperfocus in small areas that they are completely unable to give a general summary of what they are doing in the bigger picture. To do so would require them to understand things outside of their very narrow field of study.
Yes.
For a long time identifying bacteria required growing them on different media. If then bacteria didn’t grow on the media, we didn’t know what it was. However for most pathogenic bacterium we did figure out how to culture them.
Then molecular biology advanced to a level where we can amplify and sequence a single bacterium’s DNA. This has led to a continuous stream of new species discoveries from different environments.
Finding a new pathogenic bacteria for humans is still a rare discovery.