The crust of the issue is no one is under any obligation ti hand out merits (except merits sources, to a small degree).
It is recommended that one hands out smerits, as they are of no use whatsoever to the hoarder, but not everyone sees the need to search for deserving posts, and some accounts with sendable merits are inactive.
But the merit sources and willing members are doing a good job in keeping merits in circulation.