The Libertarians adopted this view of human inability to dispense with justice by establishing a just pattern of distribution. Instead of imposing a pattern on society, they limited themselves to ascertaining that the market players engage in just acquisitions and in just exchanges. Justice is not dependent on a particular distribution pattern, whether as a a starting point, or as an outcome. If the position of others is not worsened by the acquisition - then it is morally permissible. There is no morally plausible and defensible justification of the Lockean Proviso.
Exclusive ownership is the result of real-life irreversibility.
The first has the advantage of excess information, has invested work, time, effort. The act of owning involves investments and the latter relate to the future. By taking on investment risk - the first owner attains ownership. Ownership is the compensation for investment risk, setting the asymmetry straight. Profits reflect inherent inefficiency, an intrinsic compensation.