And is that the reason policy is trying to return only smallest allocations and let the big allocation holders continue selling their ones?
As Gert wrote, it is not about returning allocations.
It also seems as if you're missing a vital point:
This policy proposal will most likely increase the time period where network providers will be able to get IPv4 address space for interoperability.
Regarding what big allocation holders do, this policy proposal changes nothing. Big allocation holders cannot be affected directly by policy change. But if big allocation holders want to transfer away part of their allocations, to others, or new entrants, who need more space, that is mostly a benevolent market mechanism, as it only increases the use of these allocations.