I think the premise is flawed. Most of us have been brought up in a world that preaches “if you’re not growing, you’re dying.” That mindset is harmful in a whole host of ways. I have no idea if lemmy is growing or not, but it’s quite possible, perhaps even preferable, for a service/site/mom-and-pop shop to be sustainable without unending growth.
It’s not copium, it’s just an acknowledgment that I, and presumably many others, don’t care or need to care if it’s popular- it is already useful to me as is. In the same way, I’ve never given much of a shit about “the year of Linux on the desktop”; Linux has been useful to me as a daily driver for the past 28-ish years and neither my enjoyment of it nor its utility to me were in any way hampered by its failure to achieve supremacy of numbers.
It’s fine to use something other than the most popular service.
Now, if you think the purpose of federated social media is solely to supplant the corporate, centralized platforms, then I understand, but disagree with, your position.