Difference is that Rise in Japan hasn't been as heavily discounted as World
Chris1964 mentioned in the M-C threads; in Japan World was discounted by a bigger amount much earlier;
In as far a the PC Release, I would say a lower launch was expected World had much higher budget and was the first MH on the platform. Still it's the 2nd biggest launch for Capcom on PC and Sunbreak is bound to help with long-term sales on the platform.
This is an example of cherry picking reasons to justify a point.
Even with the price cut MH was absent on famitsu December weekly charts, so price cut was a non factor for Rise
What I'm seeing from your post is World was actually more expensive at launch, and most of sales come from launch. If anything it gave arguments to understand why World sold a bit less than Rise
What has no explanation however is how Monster Hunter Rise sold only 20% more in a console with a 250% bigger userbase (soon 300%).
World being the first PC launch is more like a problem than an advantage, as it needed to build its own fandom from the ground. It started with a ~2 million in 2 week launch and soaring past 7 million copies since then.
In defense of Rise, Monster Hunter has a heavy multi-player focus and the game userbase is still very active. World is perceived as the best Monster Hunter, it's bigger, has better graphics and is a complete game with expansion, it's less expensive and has a big community. Even for newcomers it's better to stick with World if you want to experiment a Monster Hunter game. Rise is more like a game for fans that already played MH series and wants a new entry, while World is suited to anyone, fans and casuals alike