I absolutely loved
Decado's post, he says everything I wanted to say and more. Deus Ex was a game made in the United States in the late 90s, in other words it was made in a country where conspiracies are handed down with the breastmilk and the massive popularity of the X-Files at the time made government conspiracy theories both accessible and more importantly
acceptable.
I don't believe for a second that Warren Spector or anyone in the team was a big believer in any of those conspiracy theories, they simply used them as a platform to base a game on. They didn't delve deep into any of the conspiracy theories. For instance the FEMA theory about taking over the government, concentration camps, etc. is straight out of the Reagan administration 1980s where Carter's innocuous FEMA was imbued with new and draconian authority in response to potential mass protests or insurrection because of American invasions into S-American countries. This came up in hearings about the Iran-Contra scandal, where a Democrat from Texas asked about this in an open hearing and the chairman, Senator
Inouye, shut the question down completely because of "national security" and had it confined to a later closed-door hearing.
As one can imagine, this was basically confirmation of the new powers of FEMA. This is all ignored really in Deus Ex and this FEMA power is simply stated matter-of-factly, as are most of the conspiracy theories. They just "are". They don't have a background or depth or anything. It's as if Spector and company simply mashed together all the "coocoo" conspiracy theories they could find, without much understanding or interest in them, to create a background for a story.
So if this approach had been used in DXHR/MD or would be used an upcoming DX game, they'd simply throw current conspiracy theories out there matter-of-factly without explaining them at all, use them as set pieces foundations for the narrative.
Anything from a hidden chamber filled with government secrets behind Mount Rushmore to an underground city which serves as a headquarters of the New World Order situated beneath the Denver International airport. From the Deep State to Big Tech mass surveillance. From stolen airliners to Q-Anon. Just make all of them real, don't explain them, build a story on top them. That's what Warren did and I think it would be a good move to follow his lead for a new Deus Ex.