Q:

Does socialism require capitalism, or can it be a standalone ideology? 

In short: Within the fundamental model of societal growth, does socialism only follow after capitalism, or is socialism philosophically capable of standing alone as a principle ideology during the consutruction of a society? 

Long form:
In a hypothetical pre-society, 3-5 people of the same plot of land equipped with only the knowledge of sticks and stones, band together to mark the initiation of a society with the goal to reproduce and explore/innovate within science, geography, literature, economics, manufacturing, ect.,  to establish an infrastructure of societal growth that would be fundamental to the underlying success of the advanced society their progeny find themselves playing video games in.  For simplicity, let's say the growth/advancement of the society followed a sigmoidal trend over 1000 years, where extreme growth was preceded and succeeded by a relative plateau: 
During societal development, would centralized socialism ever be favored to secure equality of outcome for each individual, at the expense of progress (natural selection by societal contribution) and available utilities (individual cost/benefit of food, water, attention, ect.)? 
Or, would capitalism, as a vehicle for 'natural selection by societal contribution', inherently be required for societal establishment up until the second plateauing of the society's growth, in which only then higher degrees of socialism could be implemented? 

Revised: (at the request to narrow the scope)
Can socialism be a principle ideology during the growth of society; or does capitalism always precede socialism? 
*socialism def: individuals and businesses own the means of production, socialize the profits to ensure principled outcome equality of citizens.  
*societal growth def: In the context of endogenous growth theory; growth curve is positively sigmoidal in the example indicating non-sustainability of high-growth phase. 
*note: I understand my question may solicit some opinion; though I do not see any material addressing this question anywhere on the web (perhaps I'm missing it); so I do apologize as I cannot guarantee succinct factual answers despite the potential validity of the question. 

A:

According to some socialist and communist philosophies, a stage of capitalism may be required, at least for underdeveloped countries. 
This is called stagism / two-stage theory.  Proponents are for example stalinists or maoists (or early social democrats). 
The opposite idea is sometimes called permanent revolution and is supported by trotskyists. 
Marx and Engels made it clear that they think that there may at least be some circumstances in which a capitalist stage is not required:

Now the question is: can the Russian obshchina, though greatly undermined, yet a form of primeval common ownership of land, pass directly to the higher form of Communist common ownership?  Or, on the contrary, must it first pass through the same process of dissolution such as constitutes the historical evolution of the West? 
The only answer to that possible today is this: If the Russian Revolution becomes the signal for a proletarian revolution in the West, so that both complement each other, the present Russian common ownership of land may serve as the starting point for a communist development.