But for projects that don't view those design constraints as very important and projects created when there were other languages that don't have the same histor

But for projects that don't view those design constraints as very important and projects created when there were other languages that don't have the same history those compromises/explanations won't help. If/when there is a better language you don't have to suffer the history of C++ anymore, just use a newer language without the history. And if the constraints for example were to make it C compatible and very fast, for many projects those may not be of much importance anymore. Other language may be fast enough and easier to write in. I think it is probable that most of todays applications has lower speed requirements than C++ were aiming for. Those who needs speed can probably still use C.