Why do YouTubers arrange meetups?

Nowadays arranging meetups is a new trend in grown YouTubers. The legends (themselves) say that meetups are arranged only to interact with their audience, their subscribers which is right upto certain extend. Though all YouTubers are not like that, most of the YouTubers arrange meetups for different reasons.

Lets consider a technology YouTuber for time being who has grown up immensely and not his growth is either stopped or it is not as it was before. Now we can assume that the targeted audience of the platform (YouTube) is attracted by him. Some liked him are his followers and some disliked it can happen to any content creator. As a human being that YouTuber want to grow more and more but his targeted audience in his domain is full. Now what should be done to increase followers?

YouTube MeetUps

As per my analogy, these YouTubers arrange meetups to increase number of followers. Now a question may come in your mind that the followers are the only once who will come for the meetups so how will he increase followers' count through meetups? I think, the followers who go for meetups are the once (mostly) who want to be like that YouTuber. They are newbies to YouTube with their new channels. As they are followers of this YouTuber, it is more likely that they are followers are that domain of content. Thus they will most probably start with their content somewhat related to that domain. Those people will have small amount followers of themselves. Those new YouTubers wont directly copy the style or kind of videos of that big YouTuber so their will be somewhat different and their follower base will also have different taste. A they are new YouTubers their major followers base will be consists of mostly their family, friends who are more into that person than that domain.

Now whenever the big YouTuber takes a meetup, the follower-cum-YouTubers will make videos including that big YouTuber to get popularity, to increase their follower base. But the follower-cum-YouTubers are many in count and the big giant YouTuber is one in count. Though small YouTubers are targetting bigger audience, it is less likely that big YouTubers followers will follow them as their content is not that grown at the same time big YouTuber is targeting 100 small YouTubers follower base which might not have known the big YouTuber. As the content also grew over time, they are likely to follow that big YouTuber. So may be that is why YouTubers arrange meet ups.

PS : This is just my analogy. I am not saying that YouTubers do this only to gain more followers but  this may be the reason and I feel nothing wrong either in doing so.