Subjunctive mood has 4 different tenses, present, passé, imparfait and plus-que-parfait. The last one is rarely used and has been for at least 30years. It's also similar to the conditional past 2nd form. e.g. "(que) j'eusse fini". For the other tenses, they are still used in sentences like "il faut que je fasse" and similar. Now, if we are speaking about the past simple (passé simple), it could disappear within one more generation. For mine (born in the low 80s), it was already "deprecated" when speaking.