I think I see what you've tried to articulate here. Effectively, a flat-plane multiverse of contemporary sociocultural sandboxes coalesced under the umbrella of an economically all-encompassing, central planning-based welfare state. (Correct me if I'm wrong, of course.)
However, I feel this doesn't address the underlying issue that leads us to the socioeconomic burnout we feel in the present civilizational paradigm. Currently, the issue isn't that people aren't free to move into smaller groups and shift out of mass society, so much as it is that there are no alternatives to mainstream residential setups.
Also, central planning seems inevitably destined to nourish the worst of humanity--through its tendency to foster that particular kind of administrative arrogance that it fundamentally requires to operate (how do you take decisions affecting vast swathes of people with varied interests, while knowing you can't escape your own biases, without having some kind of narcissism-inclined cognitive pathology?). Even sortition/lottocracy doesn't feel like a sufficiently effective mitigating factor. But maybe that's just me.
That aside, it is an interesting thought experiment. And in that vein, I shall take the liberty to suggest a modification:
First, we will retain the idea of clades but clearly define them as knowledge/ideology based coalitions/associations with a residential component hinged on being initiated into that system. So, effectively, each clade is something of an academy--with the insulation common in these cases being mitigated through technology (in transport and communication) that facilitates trade, travel, and casual interaction between the individuals in various clades.
In this sense, clade's retain their principle of voluntary membership.
Second, we will also retain the current urban environments and their monolithic culture. Clades and cities, thus, will be contemporary formats of residence and economy--particularly, their simultaneous existence makes them active alternatives to each other. People, thus, are free to choose between living in a mass society/mass culture (cities) or a kind of distinct ideological conglomeration (clades).
The distinction is that the cities would retain that increasingly-homogenous rat-race culture of global metros as is familiar to us today (in varying degrees, of course; but trending towards becoming globally homogenous), while the clades are knowledge centres that allow for people, whether children or adults, to seek and gain membership based on whether they feel the tenets of its organisation resonate with them.
Third, we remove government from the context of the clades almost entirely. Consider that the government is an organisation whose primary purpose is the maintenance and upkeep of cities. This includes infrastructure, law enforcement, healthcare--effectively anything under the purview of a central planning-based welfare state. The only part of the clade-equation that a nation-state participates in is international representation (in forums such as the UN and other such inter-national coalitions, current and future), and the provision of defense, again, only in an international context (global or regional wars between nations, etc). The election of government official can employ the original idea of sortition/lottocracy, including participation of members from the clades (since, as an extension of international representation, all individuals, whether of cities or clades, are recognised as citizens by the state).
The administration of the clades--and so, even the responsibility for their own survival, regardless of how brutally they may fail or what they choose to legalise/condone to survive (barring, perhaps, indiscriminate violence)--is left entirely up to the clades. The social, cultural, and commercial economy between individuals and groups will ensure that contact between clades and cities remain active. The clades can perhaps enter into agreements/treaties with the government that serve to recognise the clade and define the basic aspects of the concessions and limitations afforded to the clades (perhaps even using a general structure applicable to all clade's as a base)--in order to better define this interaction between government-administrated cities and self-administrated clades.
To be clear, the general framework of interaction between government and clade will define the limitations and concessions afforded the government just as much as it does those afforded the clade.
I feel this structure that offers the individual the choice between centres of mass society and multiple niche offshoot societies, while they serve as active alternatives to one another, might foster a more equitable environment in the long-term. The overarching clade environment, devoid of pure government intervention, also becomes a sort of meta-meritocracy in that only the clades able to sustainably administer themselves will last. The others will either volunteer to become subsumed under the state--or will collapse into bands of marauders intent on proliferating the vectors of their decline upon the whole system of clades and/or cities.
In an ideal iteration of this, both clades and cities will offer formats of residence while contributing to the whole, conceptualised as the nation-state or national economy, in two distinct ways (on top of, and apart from, residence): the cities contribute commercial efficiency and the clades contribute epistemic longevity.
I feel I may have overworded--though, attempting to review and reduce has still left me with this teetering verbal obelisk. Nonetheless, this was an interesting exercise in speculation. And if you've made it all the way to the end here, I appreciate your patience :)
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tl;dr: a system of clades and cities, rather than an ecosystem only of clades--done so, to provide meta-diversity rather than just diversity (choice to not choose rather than just choice between choices); and, the majority of state intervention is absorbed by cities, while clades are left to pseudo- or quasi-anarchic self-administration