Socialism is a doctrine of the average, the middling, and the mediocre. There are at least three inherent characteristics that limit achievement under socialist doctrines.
The first is that it does not have the optimizing advantage that competition provides to capitalism. Competition, and thus capitalism inherently rewards efficiency; socialism inherently rewards uniformity, a condition that is unavoidably opposed to exceptionalism.
The second characteristic that handicaps socialism arises from the concept that the value of money, like all values, is largely a matter of opinion. This principle is largely self-evident, and examples of it abound. When the stock market tumbles and investors lose billions, what has happened is that the opinion of the worth of the implicated investments has changed. The natural consequence of this is that economic growth results from providing captial to the production of goods and services that people generally find valuable. The disadvantage of socialism in this regard is that some central authority tries to prescribe what people should value, and if that authority is wrong, stagnation follows.
It is quite natural for a government to decide that everyone would be better off if they preferred fuel efficient vehicles at the expense of safety, or certain food choices at the expense of individual preference, or economic security at the expense of opportunity, but if these do not refect what the majority of peoplel value, no amount of regulation or stimulus will remedy the defect. Governments cannot force the people to want something, even if it is for their own good.
The third shortcoming of socialism is that human beings are inherently progressive creatures, and by that is meant that they will always strive to find more efficent means of pursuing individual interests. Efficiency is simply the amont of something desirable per amount of something necessary or expendable, and if the socialist limits the amount of the desirable thing, the natural human response is to increase efficiency by limiting the expenditure of something else. If the governemtn caps salaries, workers will respond by limiting the amount of effort they expend.
Socialism is a doctrine of caution, not of vitality or inspiration. It is suffused with the catchphrases of social justice and equality, but produces only artificial facsimiles of these. Socialism seeks its ends by minimizing risk, but in so doing minimizes the rewards to be gained from accepting those risks. Socialism requires that people in significant measure give up some of the aspirations, ambition and daring that is a natural part of human nature, all in the interest of achieving something that works much better in theory than it does in practice.