Lack of funding was a significant reason France didn't enter a team. Fiji, Samoa and Tonga all had an opportunity to qualify, however pulled out due to a ridiculous qualification process (held in Western Sydney with all teams expected to play three full 80 minute games in one day in like February)
Cook Islands qualified by being the only team that turned up willing to play.
Being honest, Women's RL is still in a very formative stage in many countries. Fiji only held it's first organised competitions this year, Tonga & Samoa have had a couple of years of domestic Women's RL, Italy, Lebanon & Spain pretty much kicked off their first games in 2016, Chile only just started this year (and the Women play in a mixed competition) and as for Russia who competed in 2008, no idea if they still have Womens competitions kicking around.
Come 2021, there should be greater competition for spots.