A Question.....

as the money goes--the story in the film says there WAS no more money.

As far as why they never got out other than for "hunting," I suspect that, much as language was lost, eventually the idea of any world outside their subterranean one was also lost, so they didn't think there was a reason to leave (whatever generations were around by the time they finished digging)

This plot had so many holes it made it hard to suspend logic. Let's assume (which is a BIG assumption) that 12 people were abandon because of a lack of funds to save/find them. When one has language, one does not loose that language, even though successive generations are living underground. The language and mores of the original "survivors" would be intact.

An example of this, handled more realistically was presented in Mad Max Beyond Thunderdome. Here children from past generations of isolated adults have language but the tales (tells from TV) are amusingly distorted. Distortions in stories and history occur but LANGUAGE is not lost.
In Raw Meat we have the survivor practically unable to speak at all - muttering only "mind the doors" for every occasion and need!

Additionally, once a survivor found others, along with hearing the outside noises, from hunting, one or more would have left to explore that outer world - as our human ancestors have done since the beginning of time.

I realize that one must suspend some logic for many movies but, when that "logic" goes to such extreme distortions, it becomes big plot holes in the story line. The underlying premise is too unbelievable.

I also agree with others that the pacing and odd juxtaposition of Pleasence's humor become a bit too much and make for an "out of balance" project.

Interesting for a few minutes but overall an illogical bore and waste of talent.