Seems like that was just a temporary blip:

“New data suggests that the effect was temporary, with Twitter having managed to grow its advertiser roster to 3,700 in the fourth quarter of 2022 from 3,000 in the third quarter, according to an ad intelligence firm’s report released Wednesday.

Twitter averaged 3,330 U.S. advertisers per month on average in the first quarter; 3,740 in the second; 3,000 in the third; and 3,700 in the last three months of the year.“

It’s hard to know for sure, of course.