It's not what happened: it was actually invented and developed in France by Félix d'Hérelle[1] (who taught George Eliava, the Georgian scientist responsible for the Soviet developments of the field) and used to be quite popular here too before it was supplanted by the antibiotics, more convenient and easier to industrialize, during the 70s.
Having lost all that knowledge is really a pity, and it's quite fortunate that the Soviets then the Georgians kept it going.
On a side note, d'Hérelle was a fantastic adventurer and his life is fascinating (the French version of [1] has a nice summary), even moreso than Yersin's (the discoverer of the bacteria responsible for the Plague[2], and founder of the city of Đà Lạt[3] in Vietnam).
[1]: https://en.wikipedia.org/wiki/F%C3%A9lix_d%27H%C3%A9relle