I think we're going to need to start by defining what "popular" means.
According to https://fedidb.org/software/lemmy, there are 462,745 total Lemmy users. (Note: I know nothing about this site or their metrics; I literally just Googled "Lemmy users.")
If 462,745 people showed up to my birthday party, I would feel like the most popular person on the planet.
So, I think we need to consider a less abstract figure to answer this. Will Lemmy ever be as popular as a place like Reddit? I think that's extremely unlikely, at least not anytime soon. But will Lemmy ever be popular enough to sustain an engaged community? I dunno; I kind of think we're already there.
Maybe this is the old head in me, but I remember the decentralized days of the early internet, where communities weren't oceans of people on social media giants, but rather smaller, close-knit forums and message boards. If you spent a few months interacting, you would likely get to know and have specific opinions about individual users that you would regularly engage with, unlike the sort of hit-and-run buzz style of the modern social internet. I think right now, Lemmy is almost treading a special sweet spot between the two eras, and I'm pretty happy with it.
Although I will concede that I'm as addicted to social media as everyone else is these days, and I would certainly welcome the increase in on-the-minute activity that additional users would bring.
462k are the people that have created an account, Lemmy actually has ~40k active users (and even then "active" just means they logged in once this month). I do share the sentiment that not everything has to be super popular but Lemmy really could use more people.
I appreciate the clarity, thank you. As I said, I pulled a random googled number and wasn't trying to use it as the sticking point of my commentary. But also for what it's worth, it's not exactly a fair comparison to the larger giants either as lemmy's smaller scale means it is also less trafficked by bots, fake accounts, secondary novelty accounts, etc. Depending on what source you're looking at, twitter is claimed to be anywhere between 15-75% bot or fake accounts. In general my point was there are still a large number of people using lemmy on most scales, we are just choosing to view it on the scale of established corporate social media metrics.