The real world does work this way. Businesses make business decisions based on bottom-line impact, and businesses generally push back very strongly against governments whenever a government asks them to do things that will cause them to make less money and/or waste money.
>The "infrastructure" for the targeted updates is implemented by compartmentalized teams, who will be comprised of the clearance community, and the "external" people who work with them are a part of the clearance community.
I agree that would be how it would work if it actually happened, but I think you overestimate the appetite (and even ability) of big tech to have any desire to do this kind of thing.
If you are implying that there are teams within big tech companies who secretly do this kind of thing, even against the wishes of other engineering teams (including security engineering teams) within the company... well that seems like a recipe for getting some of the company's most talented and highly paid security engineers incredibly pissed off if they ever find out — and it's very likely they would eventually find out, because it would be extremely difficult to hide this kind of thing over time.