Every professional sports league is filled with owners who are doers, those who are followers and some silent types who speak up only when they must. In a relatively short period, the N.F.L. has lost a collection of all three types of owners.

On Friday, the Houston Texans’ founding owner, Bob McNair, died at 81 after a long battle with cancer. He became the fifth owner this year to die or to sell a team, an unusual amount of turnover in a league known for its stability.

In October, the Seattle Seahawks owner, Paul G. Allen, died at 65 of complications from non-Hodgkin’s lymphoma. A week before, Alex Spanos, who bought the San Diego Chargers in 1984, died at 95. In May, Jerry Richardson, the founding owner of the Carolina Panthers, sold his team after reports emerged accusing him of sexual harassment and using racial slurs. In March, Tom Benson, who bought a majority stake in the New Orleans Saints in 1985, died at 90.

The five belonged to a fast-diminishing group of owners who were self-made business owners and more often than not came from humble beginnings. They made their fortunes in industries that boomed in the 1960s and 1970s, when they built their empires — in energy (McNair), car dealerships (Benson), fast-food franchises (Richardson) and home building (Spanos). Only Allen, who started Microsoft with Bill Gates, staked his claim in what might be considered a cutting edge industry.