Just to muddy the water a little. Like many other topics, this is not black and white and the definitions will vary according to the laws of the different countries. In past discussions people have claimed that their martial art provided them with 'self defence' when in reality the link to self defence was at the very best, tenuous. I think, for those of us with decades of involvement in the martial arts, if you turned the clock back twenty years or so we would all have claimed we were learning self defence. Heck, that's exactly why I took up boxing back in the 50s. I was being bullied at school. Understanding changes with time and experience.
So just as there is an overlap of TMA, Sport MA and Self Defence that will vary for each individual person involved, so is there an overlap between RBSD and Combatives. With the prevalence of guns and knives in countries like the US there will be more overlap than in places like the UK and Australia where if you avoid certain trouble spots you are unlikely to encounter a gun or a knife in your life.
Then, you can add your other training back into the equation. If someone, for example, has an extensive background in TMA it is likely that they will have many of the same skills required in RBSD. Sure, the training methodology is very different and it will take you longer in a TMA to get to the same level of street effectiveness, but the underlying goal is the same. If we are ever physically threatened we will have the ability to avoid a bad situation or defend against a physical assault and get home safely.
Now guys like Chris will argue, quite validly, that a number of TMAs, especially the ones he studies, have nothing to do with self defence. I would argue that there are other TMAs were self defence is a major part of the training. I would also contend that that training can contain a significant element of RBSD. Some of us teach more than one MA. How do I explain to one group or the other that their training is not as effective to defend themselves on the street? Quite simply, I don't. In fact with the problems of everyone having times mixed up in the rush before Christmas, I invited the Krav guys who couldn't make the regular training session to come to the Karate class. For me the training is almost the same and the outcome is also the same.
In other threads we have had people with no knowledge of kata talking about how it is a total waste of time. Fine. No problem there. If you don't want to learn kata, do something like Krav. No kata there ... or is there? When I teach combinations in Krav, where do a lot of the combinations come from? My guys practise kata without even knowing it.
Where I think there is a huge problem in most training, and I don't claim to have overcome it, is how to test it for effectiveness. Now in Krav you put on gloves and some protective gear and have a bit of a slogfest, not unlike what you might see in low grade MMA. Is it useful? Sure. It gets you used to hitting and being hit but it doesn't provide you with the experience to deal with adrenalin, and it still doesn't make you 'bullet proof'. In most karate places they do their sport type sparring. To me that is pretty much the same. In BJJ you are working to submit someone. Same, same. In our karate it's probably a blend of the Krav and grappling with less striking and kicking, but again, it is not being full on tested. You can make the training as realistic as you like but it will never be the same as the real situation.
The point was made in a previous post that 'realistic' training is not the same as 'RB' training. I'm not sure I agree totally with that sentiment, again, a matter of degree, not black and white. 'Realistic' training has to be in context. Realistic training in say Kendo, probably has nothing to do with 'reality' in a street context where realistic training in Krav has a huge amount in common with RBSD.
Just some thoughts.