Facing regulatory and political pressure, Facebook and Alphabet Inc.’s Google in recent years committed a combined $600 million to support news outlets globally — many of them local or regional enterprises foundering in a digital age.

Thousands of media outlets received financial and other support for everything from fact checking and reporting to training, according to the tech giants’ announcements. Some publishers express gratitude for contributions they say are essential as advertising revenue has plunged.

But several media analysts and news business executives said the funding — set to last three years — does not nearly compensate for the tens of billions of dollars publishers lost as the tech companies gobbled up the digital advertising market. Google and Facebook accounted for 54% of U.S. digital advertising revenue in 2020, according to eMarketer, a market research company.