Think of viral particles as analogous to bacterial spores or plant seeds. A bacterial spore also wouldn't necessarily evolve in a petri dish with antibiotics, i

Think of viral particles as analogous to bacterial spores or plant seeds. A bacterial spore also wouldn't necessarily evolve in a petri dish with antibiotics, it needs a certain set of conditions to exit dormancy, for example a petri dish isn't implied to have agar in it nor do all bacteria thrive on agar. The actual "life" of a virus starts once the viral load has co-opted the cellular machinery of the infected cell. Viral infections can definitely evolve when a selective pressure is put on them.