For your answer to be correct for your employer, the added productivity from your use of LLMs must be at least as much as the productivity from whichever coworker you're having fired. No study I've seen claims much above a 20% increase in productivity, so either a) your productivity without LLMs was ~5x that of your coworkers, or b) you're making a mistake in your analysis (likely some combination of thinking about it from your perspective instead of your employers and overestimating how helpful LLMs are to you).
It makes him (presumed) 20% more effective than his coworker makes him. Overall effectiveness of the team is not being considered, but that's why his manager isn't asking him :)
> And now I'm preparing for my post-software career because that coworker is going to be me in a few years.
Which implies they anticipate their manager (or someone higher up in the company) to agree with them, presumably when considering overall effectiveness of the team.
