Just a few years ago, Representative Kay Granger of Texas made history when she became the first Republican woman to lead the powerful House Appropriations Committee.

But her ascent on Capitol Hill reached a coda over the weekend when a conservative outlet in Texas revealed that Ms. Granger had not voted in the House since July and has been living in an independent living facility — an arrangement her office had not disclosed.

Ms. Granger, 81, stepped down as the top Republican on the Appropriations Committee in March and said she would not seek re-election, but she continued to serve out the rest of her term.

Beyond raising questions about whether Ms. Granger and her team had misled constituents about her fitness to serve, the episode brought renewed attention to how Capitol Hill is powered by a crop of septuagenarians and octogenarians, including some who refuse to relinquish power even far past their primes.

“Kay Granger’s long absence reveals the problem with a Congress that rewards seniority and relationships more than merit and ideas,” Representative Ro Khanna, Democrat of California, said. “We have a sclerotic gerontocracy.”

Ms. Granger moved to the senior living facility in July, in an effort to prepare for her retirement, a person familiar with the situation who spoke on the condition of anonymity said, adding that the Texas Republican had been in touch with the party’s leaders and would have returned to Washington if she was needed for a vote.