The real problem for parallel dev is ensuring parallel dev environments can seamlessly co-exist without treading on each other. As soon as one of them wants to open a port, talk to an external database or write to a shared location as part of testing you have them conflicting with each other.

Much of this is a legacy dev issue where there was never so much of an assumption that parallel ephemeral dev environments would be in play in the first place. But legacy dev is still most of dev.