Yes not all of them plays in the RWC but the same with FIFA, not all of them qualify, but all of them play rugby so what was your point exactly?
You're real funny you know that. Case in point, Zambia have been football giants in Southern Africa for years, and were African Champions recently. They're ranked 88 in FIFA I think, while SA ranked above them now have beaten full strength Spain, then reigning World&Europe champions. Zambia will never qualify for the FIFA WC methinks. In Rugby they're ranked 88. They will never be African chapions ahead of SA, ZIM, KEN, TUN, NAM&MOR, forget qualifying for the WC. Rugby giant Australia are ranked 84th in FIFA but they will probably qualify for the next FIFA WC and do well, as they've done very well before.
Your attempt at dismissing my relevant point is pitiful. It's not about who participates generally, it's about whose participation is relevant at this level. If I'm being generous, only 15 teams count in rugby, and that's been the case for many years before and shall continue to be the case. In football anyone ranked from 50-200 can be in the FIFA WC and reach the 2nd round in the space of 4 years. A team ranked 100 can be playing in the Euros 2 years from now while England don't qualify. None of this can ever happen in rugby.