They could, but most wouldn't. It's just not something they allocate that much time to. The ones who stick around after a few years, most of those would. So doing that somewhere near BB in most arts (which is usually something in the 2-10 year range) would work. But then it's a single time, and doesn't have the same effect as doing that once or twice a year.
And I don't think most programs, being run by folks who only do this part-time, don't really have capacity to offer that kind of time intensity to a larger group.
Your above post says much of what I was thinking. It speaks to the broader base of practitioners and offerings.
I would need the strict definition of a
fight camp but we have people who get ready for regional/national tournaments every year. We have 2 6-week primer courses every year. One to two hours after a regular class, which is required, so a total of 3 1/2 - 4 hours/day 5 days/week. Some conditioning but mostly sparring technique and strategy, all done during live sparring. There is a peak in the middle weeks of straight sparring for endurance; longer rounds and heavily padded.
Maybe a new definition for martial need to be created. We have traditional and sport but there are more and more traditional schools that cross over into sport. I have not head of a specific name for these. Hybrid MA?
Like it or not the definition of Martial Arts is very, very wide spread. Even breaking it down into component parts gets involved and cumbersome. MMA? Just what falls under that umbrella? Same for TMA. And there are 'styles' that do not fit under either banner.
So, to the OP; sure competitive sport MA are superior at their given competition and Yes, that can/will a have positive effect for self defense. But it has a lot of gaps that seem to be overlooked. Like longevity, aggression control, variety, inclusivity, on and on. I doubt this is where the OP was going but they should not be overlooked.
You cannot hide the fact that there are not many 40-50 year old competitive sport people still active. Compare that in contrast to the broad TMA age range and it explains a lot.
A high percentage of our late teens to 30's age range get into the sport side, mostly locally but some go farther. It is an option we always have available.
Fun fact; one of our BB's moved to the Fresno area many years ago. At 69 she competed at the Pan American level this year. Yes, it was in sparring. No, there were no submission moves but she is one gritty old bird