Ok, Mass Effect 2 was on two discs and the last disc was almost wholly dedicated to the options you could make in the suicide mission. For example, which cutscene is played when you send person Y on this part? What are the audio pieces that play during the actual gameplay? Was that person loyal, if yes, which cutscene now?
In short, there were a metric fuckton of choices, and that’s for just a maximum of ten squad mates (Zaeed and Kasumi were DLC with not a lot of interaction, so they are not on the disc) per disc.
Imagine that, but for a whole galaxy full of people. Yeah. That’s more than two discs per game, which would get piss annoying for the people playing. Consider also the fact that Bioware writers would then need to create rich backstories and development for every. Single. Person. Then we would need to do voice recording for all of them - you want 7 million plus romance options? That’s an awful lot of voice actors - not 7 million, lets say that each voice actor does ten characters - that brings us to 700,000 voice actors. The population of Glasgow in 2004 was 577,670. Then we would need to program all of the cutscenes for the romances, all of their facial movements in conversations, all of the conversation wheels.
Don’t expect Bioware to do it, it’s just not feasible, unless you want to pay a completely ridiculous amount for a copy.