The difference between the long-term experiment and the OP one's here is that the E. coli could survive many, many generations since it was growing on a limited

The difference between the long-term experiment and the OP one's here is that the E. coli could survive many, many generations since it was growing on a limited, but not depleted medium. The 'novel' bacteria in OP's text do not seem to have such a limited medium, they'd die in one generation.