If you would re-formulate this into a question, I'd say its an excellent question! :-)
Q: Would people trying to improve their own UA lead to the unfollowing of weaker users?
A: unfollowing accounts, on average, doesn't directly increase your own UA score! Nor does the opposite apply: by following a certain account, you don't directly increase or decrease your own UA score.
The entire follower matrix, currently, consists of about 150 million individual follows. Via that extremely complex network of follows, it's close to impossible to predict if following or unfollowing 1 account leads to an increased or decreased score of your own account.
As said, UA is very hard to game. Also don't underestimate its complexity, nor base any of your conclusions on a simplified assumption.
That sounds like... a pyramid.
Also, the way you are describing it, okay let's say it doesn't directly increase or decrease your own UA score, what I'm saying is that the impact that follows can potentially have in any system where UA is important is that follows become hoarded like a finite commodity which is clearly anti-social, because you've stated that following less people is better for the people you follow. Is this not the case?
It is true that by following a reasonable amount of people, your own UA is proportionally distributed best to the people you follow.
Up until today, many Steemian-beginners ask for follows("follow me and I will follow you!") But that doesn't work because it adds zero benefit, and others find that irritating so as a net consequence, asking for follows results in less followers.
Also it has nothing to do with a pyramid. All that UA does, is empower real users providing awesome content and/or helping the community.
You are getting worried by over-simplifying the extremely complex follower graph that has been on Steem as long as "following accounts" is possible. There simply is no direct causal effect to increase or decrease your own UA by following or unfollowing another account, where that "rule of thumb" would apply to every account and every follow or unfollow.
PS: this is pretty technical and mathematically complex, but we've incorporated a mechanism that effectively combats an account following nobody.
Accounts that receive follows but don't follow anybody themselves, are "dangling nodes", that would lead to a division by zero problem, and or would be able to sink-in UA. We circumvented that problem by introducing a virtual account called "Omega" (or "Everybotty" as @Holger80 and myself have dubbed it). In our computations, every account virtually follows Omega, and Omega follows every account plus itself. Then we subtract Omega's UA from the matrix, and normalize all other accounts from there.
And also, we can tune the systems behavior with varying the damping factor. No worries!
Is Pagerank used by Google a pyramid? I mean, because of PageRank people got careful about the quality of their hyperlinks, who they link to and because of that made the process of finding relevant website around certain topic way easier.
Now, we have a metric that tells us who's most followed by real users and who are bot swarm...it's a win/win, much better than the current system.
All I'm saying is that entire careers have been built out of reverse engineering the pagerank algos, and if there's money involved people will always try to "crack" algos.
and those career almost no longer exist. "SEO Expert" are now building websites that are actually doing what the are supposed to do, create value around a particular niche. Black hat is pretty much dead.
So what about this attack vector: An attacking user creates one hundred accounts. These accounts all follow each other giving them a neutral UA. Then all of these accounts follow the attacking user to transfer their UA to the attacking user.
Wouldn't this be a way to undermine the UA system?
I like the idea behind UA, I'm just worried it won't work.
Answered in the top comment!