the protomorphs evolution into the xenomorph.

the protomorphs evolution to the xenomorph has to take less than 20 years. how is that going to happen. its not like were going to spend a whole nother movie on how the protomorph became the xenomorph. hardcore fans like us are pretty much the only ones who see a difference between the 2. This is very important to me considering that the whole point of the prequels is to tell how the xenomorph was created. its not like david has more time to perfect the xenos. there is also no way that naturall selection caused these changes in the course of 20 years. for one, the protomorph is not biomachanical at all. the only thing that could maybe make sence is if during the next film, since he belives androids to be superior to humans using his own synthetic DNA in place of shaws in his experiments. this could maybe explain the biomachaical features. one other thing that i had heard recently is if the actuall xenomorph is a weaponized version of the neomorph.