Sorry this is long š
No, at least not entirely. I wasnāt saying that followers were the only factor, but generally speaking ābigger authorsā tend to have many followers and many reads. As for an author who has millions of reads and little to no followers, well Iāve known at least one of them and I wouldnāt consider them to be a big author since there isnāt recognition or popularity. Theyāre not talked about, theyāre not tagged, their future projects have little to no recognition/performance.
I havenāt looked at my follower count for quite some time, but last I checked it was in the 14-14.2k range, but I am a small author because I donāt actually have much engagement or recognition, I donāt have any well known stories with tons of reads and Iām not in the payment program. Even at its peak when I was more active on there, which was 16.4k around 2.5-3 years ago, I was still a small author, so I do know that followers are definitely not the only factor.
I donāt think a lot of reads necessarily determines how ābigā someone is and I donāt think followers necessarily determine how big someone is either, but generally speaking most authors Iāve seen in the categories Iāve put in my previous reply, small, medium, big have a corresponding number of reads ranging from a few hundred to millions but it isnāt the case for every single person. It just helps me broadly categorize at a glance.
Iāve seen people with a lot of followers who arenāt popular authors or even authors at all, but in the general scheme of things, I look at reads, popularity, chance of story success, and followers to determine my own opinion of whoās small, medium or big and from observation, those with many followers have a bigger reach, more exposure, quicker reads, more interaction resulting in more attention, and a decently sized fan base for their next story.
I donāt know personally of anyone whoās done that (but I have seen a few people called out for it that Iād never heard of nor seen prior), but I donāt think fake followers would guarantee success into being a bigger author because thatās all fake followers are⦠fake. Thereās no real interest in the authorās work, not really any engagement, exposure, shares of the authorās work etc. but in my response, I was referring to authors that have genuinely built up their fan base with real followers and have/havenāt yet reaped the rewards that can come with that.
Thatās a grey area for me, because like I said, Iāve known at least one person who had millions of reads but a small amount of followers and basically no recognition (this was back in the day of ink). If I had seen their story in more places for recommendations, or screenshots in peopleās stories, and people following them, then perhaps I wouldāve considered them a bigger author, but they themselves didnāt see themselves as a bigger author. 
I also donāt doubt that thereād be plenty of authors like her, with millions of reads who havenāt been heard of before and arenāt well known.
Iām not saying every author needs to have Ig, but I definitely think popularity comes into play in categorizing authors, more so than just in the forms of reads, even followers, (word-of-mouth, sharing, recommendations etc) and can definitely contribute to an author becoming bigger.
I hope that answer was more clear. 

Again, sorry this is so long⦠I wasnāt planning to write that muchā