There is a huge range of skill with regards to newaza. Rules and officiating have dictated this.
There are so many different styles, just like in MMA. Some guys want to get the fight to the ground, even by fighting from their backs, some will have crushing top games and look for pins, some don't want to be on the ground at all and are good at stalling and getting back to their feet. The combinations are endless.
You have to realise the difference in ground games in judo and BJJ too. In BJJ, of course BJJ guys will have the advantage, with lots more time to work funky guards, use leg locks and other forbidden judo techniques, etc.
If they're both engaging on the ground in judo competition, the judoka will have the luxury of winning by pin or turtling, standing and more easily avoiding the ground if he chooses to do so.