Randy is a legend, but machida has also fought the who's who of mma. I'm not saying he is a legend yet, but he has defeated bj penn,rich franklin,evans,shogun,randy...he is fighting top level competition such as jon jones and page.
Randy is good for his time, but i think we need to reevaluate the word legend. Randy gets a pass because at that time he was fighting the best of the best. The sport has evolved, and i don't think anyone will become a legend any time soon. The only locks i have are gsp,silva, with jon jones soon to be.
In my mind the sport has evolved so much that guys that randy was beating back in the days would not be top 5 today. Its all hearsay, but i bet no one would say a prime chuck,tito, or vitor will beat machida.
Legends are legends for what they did, not what they could still do. Couture has been around since nearly the beginning of the UFC winning the UFC 13 heavyweight tournament. He then went on to fight and defeat many of the top fighters of the day, held the belt multiple times in 2 different weight classes, opened one of the premier gyms in mma, created a clothing line to help promote mma, always fought the very best including current top 5 LHW and HW's, greatly influenced the sport of mma with his fighting style and has been an ambassador for the sport in movies etc.
Couture has been one of the single most influential fighters in the UFC/MMA and that is what makes him a legend. I would consider him top 3-5 for most influential MMA fighters of all time...
Machida has been a good fighter, he beat a couple good fighters and gave a couple more decent fights but that is it. Sure he was the first really successful karate based fighter but he still has a long ways to go to catch up to a guy like Couture who almost single handedly implemented and improved the most influential fighting style used in MMA for the past decade. Machida isn't a star, he is barely even a well known fighter outside of UFC fans, he has done little for the sport other then be a top 5 LHW fighter and honestly I don't see him becoming a legend unless he somehow can get back to the top of the food chain.