Why does this matter? Do we need to appease the shareholders or something? Do we need endless month over month growth, lest the world completely stops turning?
If there are no users, there will be no new contents added.
If there are a lot of users (many more than there are now), there will be enough people around to support all sorts of niche communities, like Reddit had.
Active user count is probably the single most important metric to whether a platform is successful and stays alive. Even above quality of content, as proven by many other social media platforms that thrive despite being flooded with trash content.
As a Lemmy shareholder, I'm outraged. If Lemmy doesn't get more users soon, I am going to stop the thrusters that keep the world turning. You have been warned.