BJJ is cyclical, modern techniques are not really new they are recycled and modified or updated.

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What happens is that certain techniques become popular, so everybody starts doing them. Over time everyone starts
learning how to shut them down, and then they get good at it.   The technique becomes useless.  Suddenly nobody does those techniques anymore for a long time. Then somebody starts again and people are caught by surprise. Their defense is not sharp.

Old becomes the new.   New modifications are usually added to improve on the original. It is important to learn these not only to prevent being caught off guard but to surprise people that are only using the current craze. These techniques can be tied to the modern ones as well.