It is not just about on-field performance how a country is graded under the Tiering of Countries System
It also takes into account domestic and pathway competitions, participation levels and governance arrangements including funding and infrastructure.
Until any of these Tier 2 Countries have the above they will always be Tier 2 Nations no matter if they play in or win World Cup Finals.
Population wise I can't see this changing either except for PNG and one has to also consider that Rugby Union is the main game in Tonga, Samoa ,Fiji ,Cook Islands.
PNG is the only one that could obtain TIER 1 status in the future out of all the Polynesian and Micronesian Countries as Rugby League is their national sport although a lot of work would be required to make that happen though.
Population
Tonga - 109 k
Samoa - 202k
Fiji - 913k
Cook Islands - 18k
PNG - 9.3 million
France may be upgraded to Tier 1 in the future as they do have 2 sides - one playing ESL - Catalan Dragons and one playing in the Betfred Championship - Toulouse Olympique.
Plus a 10 team Elite 1 and a 10 team Elite 2 Domestic Comp and other lower grade domestic comps with junior pathway systems.
Very difficult to get a foothold and increase Leagues footprint and popularity in France when Football and Rugby Union are the dominant football codes.
en.wikipedia.org