To me that sounds like a couple wanting a co-primary open relationship model with Another in triad configuration to start, and then tack on other people over time in co-primaryship.
So I'm going with that for the fictional polyship here.
Is there a point when the oneness is impossible?
I take that to mean
"Is there a point where it is impossible to add more people to this polyship?"
If so? Yup. Polysaturation point is reached eventually. More people = more wants, needs, and limits to deal with. Harder to balance all these things.
- You can only go so wide AND so deep. (polysaturation point. More than THIS is the breaking point.)
- Or choose to go wide(many people) but not very deep at all. (less bondy time spent together)
- Or go deep (lots of time spent) but not very wide. (over not as many people)
Because the resources are limited:
- non-human: money, material goods, community resources
- human:time, attitude, skills, leadership.
How many people can truly be stable in a relationship like this?
Depends on the people in the polyship and the resources they bring to the table and where their personal polysaturation points lie. I cannot begin to guess at a number. I'm not in the polyship.
I do know this is not a model I aspire to for myself. Polytangles only had an appeal for me when I was a younger adult with less obligations. Something forever Open and bringing more at my age now? I don't find that appealing.
What are the weak links in human emotional development that make this limit exist.
Apart from the limited human resources already listed? Of what time people have to give to relationship tending, the attitude they bring to the table, their skills they have to offer, and then their leadership ability/ability to take turns leading?
Maturity level for each person in each of their 6 maturities and how that plays against the levels of the other people in the polyship -- chronological maturity, physical maturity, intellectual maturity, emotional maturity, social maturity, philosophical maturity.
- Can't expect the same level of relationship skill from a 15 yr old just starting to date as you do a 30 year old with more life experience for instance.
- On the other hand, a person could be 60 and very intellectually mature but have the emotional maturity of a child -- and that will hinder the success of the polyship if there's tantrums being pitched all the time.
Communication skills, conflict resolutions skills -- kinda goes in the social maturity bucket there. But worth pulling out into the light on their own -- Life happens. People have to cope. Cope-ability level hinges in part on communication skills to reduce conflict happenings, and conflict resolution skills to get over whatever kerfuffle happens.
How far can successful polyamory be taken?
What is the unit of measure? In terms of what? Number of people in the fictional polyship? Duration of years it keeps going? What is "success?" No "original people" leave? What is "failure?" Not clear.
In general? However long these people in the fictional polyship wish to keep on choosing each other and stay in relationship with each other to mutual satisfaction. I guess that would be "successful enough" for them to be "happy enough" together?
Hmm. Interesting. Thanks for the Shiny Thought to mull over. That was fun.