Not necessarily. I think it’s perfectly possible to be a random non-famous person that builds a following because they have insightful tweets/images/content. But the risk is that if you don’t give yourself a reasonably memorable publisher name, you won’t be able to transfer that audience to another platform, because no one is going to see your name and recognize it from elsewhere.
I'm an exemplar of the person you describe above. I started my blog on Typepad in 2004 and am in year 21, with things pretty much as they were in the beginning. When/if Typepad collapses (there are those who say it already has, since they stopped adding new customers in 2020 after being sold and posting is VERY janky and broken since then), I'll find a new home under the same brand name.
Back in the day, around 2010-2012, I averaged 15,000 page views and 10,000 visitors/day.
In recent years it's been around 500 page views/day, so about 3% of where I was at maximum blog.
The nice thing about being this marginal is that I can easily respond to each comment/email.
A lot of us are just busking on the street corners.