Hi, folks. Voice here.
Being a software developer myself, I've had keen interest in ownership rights for a couple of decades and keep up with the tides of public law with respect to copyrights and ownership... at least in some regard.
A work such as VMK has many legal facets about it; branding, sounds, source code, gameplay concepts, and so-on. Each of these are elements that have some sort of ownership claim. For example, the likenesses of the characters are artwork in the legal sense, and although they may be incorporated into the game, they are still works of art that in and of themselves can carry copyright and ownership protections.
So, therefore, it becomes a problem if one were to create their own work (a web game, in this case) and use these pieces of artwork without permission. A complete change of artwork would be necessary... an expensive proposition. It's not impossible... the owner has many options to allow the use of their creations; licensing, royalty agreements, or even agreements for royalty-free use. But, that is up to the creator of the work.
Then there's the issue of look and feel. This is an area I can say that I am somewhat of an authority on due to a lawsuit that the company I work for got involved in... in fact, it set legal a number of precedents for creating look and feel in commercial software. The bottom line was the ruling in Federal court was that look and feel was considered a created work and that public display of the look and feel did not constitute a submission into the public domain. It would then be quite risky (in the legal sense) to create a work that is substantially based on the look and feel of another work, especially when there are references to that fact in either private design documents or public discussion.
Now, all of this came into question in 2006 when the Library of Congress (who is tasked for research for Congress, and thus the decisions of the Patent and Trademark Office) decided that they would make an exception to copyright claims for what they termed "abandonware", which was loosely defined as software that was created and protected under copyright, but which was not actively being produced or marketted anymore. Their decision allowed for the archival (copying) of the software, but did not go so far as to declare the software (including the elements of the software such as images, sounds, and look and feel) as public domain. This was a very loose decision, but the spirit of it was basically to allow enthusiasts and collectors the ability to circumvent copy protection and avoid licensing restrictions, but only in the capacity of preserving it... not for redistribution or sale.
So, what does all of this mean in relation to VMK?
Basically, VMK is still the property of the Walt Disney Company (or whomever they licensed it from... I'm not up on that aspect of it). They still own the likenesses... they still own the look and feel... they still own the source code. So at a minimum, to avoid a legal issue, agreements would have to be made between them and potential new developers for use of those elements individually. And while VMK might very well fall under the "abandonware" category, it would be in the sense of the work as a whole (executable code and all), which is not likely in the hands of anyone outside of the organization. And even if it were, to create a new usable version of the site wouldn't fall under the "preservation" decision of the Library of Congress.
Therefore, it appears, that unless the Walt Disney Company entered into agreements for the continued development and marketing of the site, it is highly unlikely this will happen. And if it does, the developers are easily setting themselves up for legal struggles... and those don't come cheap.