Yes, as with everyone especially impulsivity lessens over time, but it doesn't mean everyone who has BPD will simply stop having it if they just wait long enough. And even when symptoms lessens, most still have significant problems functioning and have low GAF scores (global assessment of functioning). There is also the hypothesis that people with BPD just learn how to avoid triggering situations and relationships, and I mean pathological avoidance leading to isolation. People still suffer.

BPD has a high suicide rate and the older people get the more lethal the attempts, add do the fact that every attempt increases the chance of completion I think it's not a good idea to let people believe it's no big deal that will just go away like a cold.