He said it was "little more than a gimmick"
I'm well aware what "he said", JCF, because I'm the "he" who said it
I'll stand by the comment too. Despite your concerns being for the most part quite accurate ones, this discussion needs to be placed in context.
It's quite obvious that the OT poster is planning a potential system upgrade for a machine which gets put to work at gaming and everyday productivity. That's obvious from this thread and from other threads the fellow has participated in recently.
The original post where I made the comment you've objected to carried clear acknowledgement that multi-core processors will enhance performance in relevent applications. To expand upon that, 'relevent' in practical terms means professional level workstation usage, basically. Heavy-duty, specialised applications areas and heavy-duty server usage. It does not, at this point in time, mean gaming or everyday productivity. It won't do so for a long time yet, and quite possibly never will.
It's also rather obvious that the OT poster is making inquiries about the things because he's heard of their existence and has gained the impression that they are a relevent item for him to consider. Quite a lot of people have. It's in the interests of the manufacturers that these things get distributed widely to reviewers who will rant about them, and promote them to 'enthusiasts'. Should the day ever come when software in general usage actually needs the things they'll be in more general circulation and will be much less expensive. Units sold now return cashflow. Units sold now, unless sold for the purposes they're suited to, are purchased for basically no real benefit.
Their promotion for anything else other than being put to work at the specialised tasks they are suited to is basically a marketting gimmick.
Personally I highly doubt that quad-core CPUs ever will become an everyday part of PC gaming. If they ever do then it'll be a long way off yet. Grabbing one of these to basically 'future-proof' a gaming PC sem a rather silly thing to do, IMO. I believe that any semblance of suggestion that they are an appropriate choice for such systems is basically a con.
I might well change my mind in a couple of years time, though. By then it might seem more probable to me that adding a quad-core CPU will future-proof a gaming PC