My guess is people interested could implement ANY location code with a local browser extension - Using firefox something like greasemonkey will help.
The OSM server part does not need to have support for all of the OLC, W3W or whatever we come up with tomorrow. As we have right now with some Mobile Apps which do support it, others dont.
When OSM generates permanent location URIs they are either to an OSM object, or to a lat/lon.