The Massachusetts Taxpayers Foundation, a business-backed watchdog, is expecting a drop in revenue of $3.9 billion compared to initial estimates, according to its president, Eileen McAnneny. Others projected a more positive picture, though they included little good news for this year. There are 420,000 fewer people working today than before the pandemic hit, according to McAnneny, who said Moody’s Analytics projects that in July 2022 — the start of fiscal year 2023 — there will be 300,000 fewer employed in Massachusetts than during this past February. Fewer people working can mean a drop in the withholding and sales tax collections upon which the state relies.