Typically the most depressing explanation for things turns out to be correct, so most likely there have been no aliens and it's just sold out groups of people working behind the scenes of institutional powers to use scientific advancements to further the dominance of their inbred masters, these inbred masters know that people won't worship and fear them personally so they need a front like the 'perfect' AI or fake aliens which they can puppet, and even if it doesn't work it still serves a purpose like psyops and diversions, but ultimately it's still just creepy inbred sociopath families with grandiose delusions, ironically sometimes the NPCs "get it" more easily because highbrow psyops go over their heads, so they're not trying to explain to themselves why the government is suddenly talking about "aliens" because they just live with the vague general understanding that it doesn't matter what the government says unless their access to resources is involved