Let's make a list, for each additional ending, you have to do several things:
The Writing staff has to actually go about developing and writing the ending, the lead-up to the ending so it makes sense, etc.
New voice acting work for everything associated with that ending.
New ending cutscenes.
Plenty of additional scripting and potentially adding more quests.
The design of additional assets and special effects in order to complete the new ending.
All of this work is both time consuming and adds additonal costs to the project.
So multiple endings takes more development time and is more expensive to make. Also, take into consideration that gamesas will have to do a retcon so there is only one "real" ending scenario that effects the lore in future games and it can be quite easily argued that it's not worth it.
And what do you care, you working on the project all alone or something? i m saying if it its functional, if they can make it, is it alright with you? why you anolyse to me how they make it? i dont care