The reason for the world championships is that countries can fund athletes to go. It can be an opportunity for riders from poor countries, who may not be able to get sponsors due to a lack of visibility or races in their country, to compete against the best in the world.
DH is an expensive sport. Most people in the world couldn't afford to race world cups as a privateer
Slightly related, I've seen a lot of points of the selection process for team riders representing their country in the world champs and in the cases I've seen it's all been about throwing tons of money at it and getting some exposure:
Exhibit A - A young rider with social riding parents wins a few club races in a category set up to give that rider the win. The other entrant (read that again, the only other entrant) is a hack, a person who comes out for fun and to meet new folks. The parents then market the young rider as a winner, beats all in it's path. The local club (staffed by the parents of the young rider) then think there's a serious lack of racing in the area and rally the surrounding clubs into creating a series that the elite riders can all get together and race in! Let's make this series recognised as a way to gather some UCI points! Again, this series has a category put in place for the young rider to win. The marketing machine rolls on, the young rider races a few national rounds and gets fucking schooled in the correct category. No big deal, we'll enter this young rider into every possible race Australia wide just to garner some support and keep brainwashing the local media into thinking this young rider is anything other than Mum and Dad's play toy. The machine rolls on.............the young rider offers a cash bonus to a team to ride for the team, thats not entirely unheard of but the rider is paying a team to wear their colors and sponsors. The young rider then gets a passport and uses the ammo that it has enough points to enter a world cup!!!! Yay, thanks Mum and Dad! The young rider is marketed extremely well locally and says it is amazing to compete competitively in a world cup finishing in the top fifty! The top fifty of the world! Wow!!!!!!!
There's 51 entrants. The young rider is in a four lap race and is lapped by the entire field on lap two. The rider finishes in position fifty after another rider pulls out. The next scheduled race starts while this young rider is still on the course. Good result though! Top fifty! That gives enough momentum to the machine to enter another one! This time around it rains and the young rider bails on the first lap, the local media release states the rider as saying "I had a mechanical failure on my bike that forced me out of the race". The (insert brand name) mechanic tells me that there is nothing wrong with the bike and the rider bailed because it hasn't ridden mud before.
The machine rolls on. The rider manages to snare an entry into an Enduro world series race. The rider rocks up to the start line with a borrowed fullface that is two sizes too big. The rider does the first stage and crashes more times than Windows '95 and again says the bike failed. The local media machine is fed more lies stating that the rider couldn't get a finish because of other entrants crashing on the course and holding the race up. The rider comes home from a super successful journey racing across Europe, finishing in the top fifty at one of the biggest races in the world!
The young rider gets another entry to an Enduro world series race and enters the pump track challenge at the same event. The young rider Rolls out of the start gate and snap's it's wrist on the first touch of a bike in that country. The media then reports (this one is the best, it really is) that the track is unsuitable for riders of this caliber and should be changed!!!! The machine rolls on..............The young rider gets a spot on a national team and enters the world championships for the given category. Gets lapped twice by the leader but is stoked to finish it's first race overseas! The media being pushed onto people does not say that the rider is the slowest rider in the world but still, Mum and Dad are proud to work hard and fund their child's dreams! Rant over. /
I know a lot of riders are picked on skill and results but giving someone a gig just because the funds are there is something that needs to be arseholed from sport. I'd rather watch a field of skilled riders over a field of cashed up hacks any day. The system reeks of pooh and is never straight forward for a new comer to understand.