If you want good outcomes, emulate the behaviors of purposefully successful people

A colleague brought to my attention the Dunbar Number. From Wikipedia:

Dunbar's number is a suggested cognitive limit to the number of people with whom one can maintain stable social relationships. These are relationships in which an individual knows who each person is, and how each person relates to every other person.[1] Proponents assert that numbers larger than this generally require more restrictive rules, laws, and enforced norms to maintain a stable, cohesive group. It has been proposed to lie between 100 and 230, with a commonly used value of 150.[2][3] Dunbar's number states the number of people one knows and keeps social contact with, and it does not include the number of people known personally with a ceased social relationship, nor people just generally known with a lack of persistent social relationship, a number which might be much higher and likely depends on long-term memory size.

While generally agreeing with Dunbar's observations, Christopher Allen points out

However, Dunbar's work itself suggests that a community size of 150 will not be a mean for a community unless it is highly incentivized to remain together. We can see hints of this in Dunbar's description of the number and what it means:

The group size predicted for modern humans by equation (1) would require as much as 42% of the total time budget to be devoted to social grooming.
...
My suggestion, then, is that language evolved as a "cheap" form of social grooming, so enabling the ancestral humans to maintain the cohesion of the unusually large groups demanded by the particular conditions they faced at the time.

Dunbar's theory is that this 42% number would be true for humans if humans had not invented language, a "cheap" form of social grooming. However, it does show that for a group to sustain itself at the size of 150, significantly more effort must be spent on the core socialization which is necessary to keep the group functioning. Some organizations will have sufficient incentive to maintain this high level of required socialization. In fact the traditional villages and historical military troop sizes that Dunbar analyzed are probably the best examples of such an incentive, since they were built upon the raw need for survival. However, this is a tremendous amount of effort for a group if it's trying not just to maintain cohesion, but also to get something done

This focus on purposefulness is something I see in the work Family scholarly culture and educational success: Books and
schooling in 27 nations by M.D.R. Evans, et al in which they point out that increasing numbers of books in a home is predictive of good life outcomes (in terms of education attainment and other desirable outcomes).

This can too easily be seen as a call to make sure that every home with a child has 100 books (a very rough break point for increasing positive impact). The problem is that the benefit is not in the number of books but rather in the attitudes and behaviors which lead to the accumulation of books, i.e.

scholarly culture – the way of life in homes where books are numerous, esteemed, read, and enjoyed.

You can't be successful having the things successful people have, only by behaving the way successful people behave. To attempt the former while ignoring the latter is a guaranty of unintended, and usually dreadful (see the 2008 housing bubble as an example), consequences. Regrettably, under the banner of social justice, our social policies are often focused on ensuring the simple replication of material outcomes rather than focusing on the development of the behaviors that lead to desirable material outcomes.

Goes back to the thoroughly Victorian commonsense observation

Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime

But how do you teach people to love, esteem and read books of their own free volition?