The dismal state of the economy is the main reason many companies are reluctant to hire workers, and few executives are saying that President Obama’s jobs plan — while welcome — will change their minds any time soon.

That sentiment was echoed across numerous industries by executives in companies big and small on Friday, underscoring the challenge for the Obama administration as it tries to encourage hiring and perk up the moribund economy.

The plan failed to generate any optimism on Wall Street as the Standard & Poor’s 500-stock index and the Dow Jones industrial average each fell about 2.7 percent.

As President Obama faced an uphill battle in Congress to win support even for portions of the plan, many employers dismissed the notion that any particular tax break or incentive would be persuasive. Instead, they said they tended to hire more workers or expand when the economy improved.