chisauking,
Apparently you didn't read my post -- I told you the basis of my opinion: experience. I've seen firsthand what skilled groundfighters can do, what persons skilled in takedowns can do. I've seen this, as well as experienced it myself, while fighting. By "real fights" do you mean streetfights? Assaults? What?
I find it interesting that you used the phrase "club sparring with rules or actual street fighting experience" -- that demonstrates one of the major fallacies associated with "streetfighting": the negative effect of "rules", or limitations on what you can do.
First of all, there are always limitations, or rules, even in streetfights -- unless one wants to go to prison. For example, one can't use deadly force unless one's assailant does (typically we're limited to the same level of force our opponent uses). So if he swings at you and you crush his windpipe or gouge an eye, you're going to prison. For me, that's not much of a "self-defense"; I'd rather get hit than go to prison! Some of those rules as imposed by society and some by ourselves (what we believe is ethical or moral).
And while rules or limitations can restrict us from actually using our method (for example, a wrestler trying to fight in a kickboxing tournament), "no rules" or NHB fights typically allow any and all methods but just limit the "dirt" or "foul tactics" (like eye gouges, etc.). They refllect, if you bother to look at most "streetfights", how fights typically "look" (fwiw, I've been in a few streetfights and never been eye-gouged or fish-hooked.). Some may believe that those restrictions prohibit them from really using their "deadly" fighting skills. But the reality is just the opposite is true -- these restrictions actually help us develop our fighting skills since we can practice nondirt realistically.
No one really "practices" that dirt realistically, i.e., really puts them into their fighting practice (you can't without harming your training partner). So they never really develop them. At best they do them as sort of a mock-defense. On the other hand, by removing the "dirt", one can practice (fight) full-out as one really would do it, and thus they develop better skill doing those things. Removing the dirt actually permits us to practice realistically and develop greater skill; it's a strength rather than a weakness. This has been proven over and over again by experience.
What that means is that the dirt is theory -- it is never really done as it is meant to be done: one practices mock eye jabs and pretends it will land, that it will have the proscribed effect, etc. But what dirt does is provide theoreticians excuses for not fighitng ("I would, but I'd have to kill you"). What they will find if they ever give themselves a chance, is that good fighters easily deal wtih the dirt (in fact, I love it when folks give me the "I will only mix it up if I can use my deadly techniques" routine; I know that means they have no fighting skill. Typically, I'll tell them to by all means use them since I know that means they'll be trying to fight with things they've never developed! It just makes it easier for me.).
Tactics are context/situation specific; our fighting skills are not. If I can deal with a punch in the ring, I can deal wtih it in the street. The venue doesn't matter. The difference is the tactics -- in the ring I may continue to fight whereas in the street I may hit and then run. Different tactics for different situations; the skills remain the same.
For those that cling to the notion of dirt, let me ask you this: do you rely on it? Would removing it really change how you express your WCK? Can you deal with a punch without it? And that's what I mean by the skills being unrelated to the venue. Can anyone say, "I can deal with a punch in the street but not in the gym?"
Certainly there are aspects/elements on the street that make it potentially more dangerous than the gym. But our core fighting skills work in both. And, how can anyone believe that they need less skill in a more potentially dangerous situation. Swimming in the ocean is more dangerous than swimming in a pool; but if you can't swim well in a pool, you're not going to fare well in the ocean.