I didn't say the other variations don't exist...I said the less intelligent Hulk is the main version by a large margin over the past 55 years. The very first incarnation was grey too...but that doesn't change that the Hulk has been green the overwhelming majority of the time.
As already said, you're completely wrong here.
We had a smart Hulk as early as the first Hulk comics by Stan Lee, his personality/intelligence being more or less like the Gray Hulk (which became so famous with Peter David's run). Only after many issues (actually in Tales to Astonish #66) the first signs of the Savage childlike Hulk were seen. But even then, there were some times (like in TTA #69) where his original incarnation appeared.
Of course, during a big part of the 60s and a the 70s the Savage childlike persona was the dominant one; it became very famous!
However, in the early 80s (with Bill Mantlo) a very smart Hulk, controlled by Banner, lasted for many issues, before turning into the Mindless Hulk incarnation for a good time.
John Byrne came to make some changes in the character (his original plan was to remake the Hulk, with his original persona, mean and smarter, but also smaller and less powerful, like in the early days.), but he didn't last in the book, and Peter David took over, turning the Hulk into the original Gray Hulk at first ( for much of his run), and the creating the Merged Hulk , a combination of Grey Hulk and the Savage Hulk (whom Peter brought only for a couple of issues for the merging to happen). Peter wrote the character for 12 years, from the mid 80s to the mid 90s.
After he left the book, Marvel tried (with Byrne, again) to make the Hulk a mindless, murderous being. It didn't work and they had to call Paul Jenkins to change the book: his run featured the Grey, the Savage, and the Merged (called the "professor" ??) incarnations, and hinting on more incarnations (an evil, "devil Hulk"). That was the status quo for about 20 issues.
Then, Marvel (again) tries to turn the Hulk into a mindless monster. Not only he was mindless, he was mute for the most part (fans called him the "Zombie Hulk"). That was the Bruce Jones run, which, as an horror book, worked for a couple issues, but went nowhere fast and lasted too long).
After that, Marvel gave the keys to Greg Pak, and we know what happened: he wrote Planet Hulk, World War Hulk and had a long run in the Incredible Hulk, becoming one of the most popular writers of the Hulk ever. And his Hulk was one very close to the original: mean and considerably smart, not unlike the original!
Jason Aaron had a short run, after Pak, but he utilized a smart Hulk too, not unlike the one Pak wrote.
Mark Waid, after Aaron, tried to write the Hulk, but I don't think he even knew which Hulk he was writing: he was savage, sometimes mute and when he spoke, he sounded really dumb...
Gerry Duggan took over the book later, and he wrote a very smart (super intelligent) Hulk, of a short run.
That's it. The Savage Hulk has not been the main incarnation at all. That's been the case since the early 80s.