SAN FRANCISCO — After a succession of devastating wildfires in the last four years, tens of thousands of Californians — many with broken spirits, many homeless — may now lose out on compensation from the company that was to blame.

A deadline for victims to file claims is less than three weeks away. About 30,000 have done so with the help of lawyers, along with 1,500 acting on their own. But the deadline could pass without claims from as many as 70,000 others eligible for compensation.

They include Steve Kane, who fears he would take away money from those needing it more, and Kelly Boyer, who says he can’t prove the value of all his losses when the town of Paradise was destroyed last year.

The filing deadline, part of the bankruptcy case of Pacific Gas & Electric, California’s biggest utility, is the victims’ chance to piece together at least parts of their shattered lives. The stakes are high: If people like Mr. Kane and Mr. Boyer do not file claims, investors in the utility — whose equipment has been blamed for several major fires — will retain that much more.