There can be such a spiral if people are delegating to you according to your RoS rather than because they trust you and/or want to help you because they are your friend, or one of your thankful follower on YouTube e.g . (And if they have good reasons to believe the expected RoS of your pool is the same than another one).
This highlights that this was kind of ridiculous to incentize people to delegate according to RoS, when RoS depended on luck. It’s not because you were lucky or unlucky in the past, that it will be the same in the future.
However, no sane delegator will touch you
When I was lucky with my pool some people delegated high amounts to my pool, only to take it away few days latter, when realizing I did not find a magic formula, but was just lucky. From what I’ve seen it happened in many pools.
Fortunately, on the mainnet you will be rewarded on apparent performance. This measure can include an assessment of how well you do against your statistical behaviour. You will be higher in the ranking than on the ITN, there will be consistency of rewards, and you can attract delegation. You will be a desirable pool.
Yes that’s a very good thing, but it does not change the point of this post, it’s something else.
You could also, if you choose, use pledge to make your pool more desirable
With the above formula it would not work if you are a small pool, as showed in the technical post
The main protocol parameter to be concerned with is “k” rather than “a0”.
I do not agree with that. k should ensure there are at least k pools, but not prevent that there are more if people want to. High a0 will imply there cannot be more than approximately k viable pools, by whipping out small pools.