could palantir consulting be replaced by LLM in the hands of a half competent hacker?

No.

1. Palantir isn't selling consulting as much as Palantir is selling the confidence you get from buying a name brand. It's the same as paying for McKinsey to provide justification to do what you already want to do.

2. Palantir actually has some good core tech. An in house team can probably do a better job just because the incentives are better aligned, but they'll be starting from behind and have to catch up.

3. LLMs aren't at a level to replace a team of FDEs. Maybe in a couple of years. The role requires too much understanding of the human systems, and too much initiative to keep the ball rolling/acknowledge and deal with real problems.

Seriously what did LLMs replace or can replace? You are living in a world of dreams

No one got fired for buying ~IBM~ Palantir. (Well...)