“The California Dream is predicated on upward mobility and the upward mobility cannot exist if people can’t afford to live here,” Mr. Newsom said in an interview. “The issues that are highlighted in terms of how we are not performing are legit. The richest and the poorest state. It has to be addressed.”

Mr. Cox, in contrast to Mr. Brown and Mr. Newsom, said he did not think a recession was necessarily in the state’s near future. Still, he described California as a place that had become increasingly difficult to live in.

“The economy has grown,” he said in an interview. “And it has obviously helped people at the top. And everyone is working, the unemployment rate is pretty low. But people can’t make it here. And a lot of people are thinking of moving.”

Many of those people who are moving out are younger residents, heading for places like Texas, Arizona and Nevada, apparently after concluding that California has become too expensive, according to a report by the state Legislative Analyst’s Office.

Economists also expressed concern that the exit of Mr. Brown could open the way for more spending by the Legislature. Mr. Brown has a reputation of pushing back on expenditure demands by the Legislature, unions and other interests that he saw as potentially wasteful. Mr. Newsom, who polls suggest is likely to win this race, is a former mayor of San Francisco who has appealed to liberal voters and has the support of the California teachers’ union.

“What Governor Brown has done is try to maintain a certain amount of fiscal discipline in his party, which I don’t see the next Democratic governor doing,” said Juliet Musso, a professor of state government at the University of Southern California. “I haven’t heard a lot of talk about fiscal reform, and that’s not something that’s going to play with the base he has been speaking to.”