Those works you mention that are "completely different" from their source material might be great, but if they're so different do they really gain more than they lose from not being a wholly original works instead? The question isn't whether the Bixby Hulk is good, it's whether it wouldn't have been better off just being wholly original series The Wandering Hyde or whatever.
As I said, I think that's misunderstanding what "original" means. Laypeople have this belief that originality requires pulling something completely out of thin air with no precedents, but all creations are reworkings of existing elements in some way. Even if the title and the character names are different, the character types and traits are familiar, the story uses an established structure, etc. Stories are like sentences. They're only meaningful to the audience if they're put together from familiar terms in a recognizable pattern; otherwise they're just gibberish.
All art is based on transformation. Sometimes the transformation is minimal, e.g. in Andy Warhol's paintings of soup cans, and sometimes it's so extreme you can barely recognize the source, e.g. in much of Picasso's work. It's a continuum. There is no point where you can say it's gone "too far" from the source. Would Picasso have been "better off" just painting random shapes instead of abstractions of real people or objects? Of course not, because that wasn't what he was trying to do. He chose an existing starting point for a reason, because that grounding in the original image was still part of his creation just as much as the extremeness of the transformation. Both the similarities
and the differences were part of the substance and statement of the work. You can't separate them.
In the specific case of
Hulk, I'd say no, it wouldn't have been better to be unconnected to the source. After all, the TV series created a whole new generation of fans and brought new attention to the comics character. Look how much the Marvel Hulk movies and
She-Hulk have evoked the TV series despite the near-total disconnect between series and comics. As different as the series is, it's become an inseparable part of the Hulk's pop-culture footprint and has fed back as an influence on the source material. Because that's how creatiivty works. Ideas evolve and transform, sometimes unrecognizably, but that doesn't mean they aren't still connected. And that's the value of keeping the recognizable title and names and imagery even when everything else is changed -- because it preserves that connection and allows the ideas to feed back.
(Though granted, I understand in Hollywood there's sometimes not really a choice because of legal issues. If there's a paper trail showing that your concept started life as an adaptation of something, then that's what it is in the eyes of the law, even if it's now completely unrecognizable. You couldn't go and turn it into an original work even if you wanted to.)
Granted, there are some cases where the changes are so extreme that I do wonder why something is even treated as an adaptation at all. For instance, The CW's
Kung Fu is nominally a remake of the David Carradine series, but it's got almost nothing in common aside from centering on a character who learned kung fu in a Shaolin monastery. But in a way, that complete difference is why the connection is relevant, because the new show can be read as a response
to the problematic elements of the original show. The original was developed as a starring vehicle for Bruce Lee, but ended up putting a white actor in yellowface makeup in the lead role, which is highly regrettable in retrospect. So the new show, which has a mostly Asian-American cast and showrunner and is very rooted in that perspective, is like a do-over, getting right what the original got wrong. Sure, they could've done the same while giving it a new name, but then it wouldn't have been so clear that it was a response to the original. Sometimes the point is to emphasize the contrast.
The thing is, creativity is a dialogue. Every work is a response to things that came before it. Sometimes it's a close adaptation, sometimes it's a highly revisionist or contrasting adaptation, sometimes it's a clear pastiche or parody under another name, sometimes it's just within the same genre or using similar forms and ideas. But those things all blend together, different hues in the same spectrum, and there aren't any clear dividing lines you can draw. It's up to the individual creator to decide.
