Yeah, there is really no real competition here.
Dream Theater's quality may vary from album to album, but they are relatively consistent, and while not every record may not be to everyone's taste, they generally seem to know how to keep the bulk of their fanbase happy. Plus they have released albums on a very regular basis for the entirety of their careers, never making their fans wait too long for the next record, and that is part of the reason I feel they can still be considered a current and relevant band within their style of music. Some may say they have become formulaic, but I say they are just honest with themselves and recognize what they are and do not try to be anything they aren't. There is something to say for consistency, after all. They are a progressive metal band who knows that they are a progressive metal band, and they know who their audience is. While they certainly work within a set creative "box", they are at least one of the finest examples of their genre. Their name is practically synonymous with the progressive metal genre, and their level of success reflects their commitment to their art.
Queenrcyche are nowhere close to DT's level anymore. True, their early albums were stellar. Operation: Mindcrime is one of the most definitive progressive metal records of all time. Plus they briefly grasped a high level of mainstream success with Empire that even DT couldn't reach. But after that, and especially after Promised Land, they just lost their way, started chasing trends, and in the process forgot who they are. They attempted to retain their Empire success by trying to fit their sound to whatever was the flavour of the moment, and they lost a lost of respect and loyalty in the process. By the time Tate had full control over the band on Operation: Mindcrime II, they were already a nostalgia act, drawing in fans who just wanted in vain to hear another "Silent Lucidity" or "Eyes of a Stranger". They've gotten better since they booted Tate, but they're still surviving more on their past then their current output. They need a killer new album to make them relevant to the young prog metal fans of today, and while their new stuff is good, I'm not sure it's good enough to draw that kind of interest from today's metal fans.
As for Fates Warning, they still have a good deal of respect among the underground metal scene, but they never managed to break into the mainstream, not even the relatively minor success Dream Theater received. It's sad, too, because I think they really deserved it, since they had some excellent records, but for whatever reasons, none of their albums quite good enough to get the attention needed to take them to the next level. And after twenty years of slugging it out playing clubs or opening for bigger bands, they just kind of faded away as Ray and Jim gave more attention to their side projects. I'm glad they're still around playing shows and putting out albums, but they're not exactly blowing anyone away with their new material. And after almost a decade break from the studio, generating interest in a new record from a band that was never that big to begin with is difficult, to say the least.