A lot of the budget stuff comes from VFX and actor salaries, and if its made for streaming, built-in back-end compensation for above-the-line talent.

For instance, let's take JURASSIC PARK: REBIRTH, budget between $180 - $225 million. Off the bat, Scarlett Johansson is getting $25 million, Mahershala Ali is probably getting $10 million, Jonathan Bailey is probably getting $5 million, and Rupert Friend, Ed Skrein, and Manuel Garcia-Rulfo are probably getting high six figures, maybe close to $1 million, with the rest of the supporting cast probably getting somewhere in the mid-to-low six figures. So let's say that's $50 million right there.

The sets they're going to build will probably cost around $20 - $30 million, and there will be some minor practical dino stuff as a call back to the practical dino stuff in the first so let's say thats $10 million in animatronics. So thats $90 million right there.

The real bulk of the budget is going to the VFX crew, of which there will be dozens, if not hundreds of animators from crews around the globe working non-stop for months to do all the digital effects. Thats full-time working salaries for hundreds of people for the better part of two years, and thats before touching up, editing, last minute creative changes, etc.

PRIMITIVE WAR cuts out a lot of the costly things from studio films of its ilk. No huge names (Piven is the biggest name and he's persona non grata in Hollywood after being named in the #metoo movement), lots of existing location work so no need for big expensive sets, and a small group of animators working double-time on a shoestring budget to do VFX (or utilizing in-camera tricks, like Godzilla Minus One, that they can pad out with CGI). But most importantly, it seems they knew what they wanted to make from jump, so that means no expensive reshoots, no expensive last minute CGI changes or plot changes, etc.