To be fair, the Alien series has always played it real fast and loose with "science" since the first movie. Faster-than-light travel is "scientifically" impossible, as is artificial gravity as portrayed in the movies. The Alien itself is an "impossible" creature with abilities beyond anything we know of (such as the gestation period, rapid growth rate, or the ability to stick to walls, to name a few off the top of my head), and the acid blood is wildly inconsistent from one scene to the next in order to serve the plot. The motion trackers shown in the first two movies couldn't function the way they're depicted, as is stacking 99 10mm caseless bullets in a Pulse Rifle magazine as shown.
Is the Alien series "science fiction"? Well yeah, when it suits the plot, or when it's trying to make a thematic point. But it isn't hard
science fiction, and the science goes right out the window the moment it doesn't serve the story being told.
Not at all... Your take is just objectively inconsistent with what transpires from the movies... It is just your unsubstantiated opinion... 😁 and why would I wanna stop you making me laugh...? Two different beings flying very identical ships... gotcha... And can you quote what Ridley said...? I do not have the book... But I agree, a retcon is usually a lazy narrative tool when you do not want to do fit your prequel to the original but rather change the original to fit your prequel... Very lazy and creatively bankrupt way to address the elephant in the room...
No, it isn't "objectively" inconsistent - the Derelict and the Juggernaut are different shapes, sizes, and designs, and the Space Jockey corpse looks similar to the Engineer "flight" suit, but the Space Jockey is much, much larger and has radically different proportions.
If Ridley Scott wanted to make the Engineers and their ships 100% identical to the Space Jockey and the Derelict and erase all doubt, he absolutely could have done that. But instead he made a conscious choice not to.
Why do you think that is?
I don't have the Prometheus art book handy to get an exact quote (my copy is still in a box, I'm still unpacking), but he briefly mentions the Space Jockey and says something to the effect of, "When I was making 'Alien', the Space Jockey was a giant corpse. And then I got to thinking, what if it was a man in a suit?"