No Stupid Questions

Well, I'm not sure what level of familiarity you have with martial arts/combat training. Or with what goes into "stage" combat, or fifty choreography.

But there's no single answer here. It's going to vary based on the production of the film/show/play, and the individual actor's interest/ability.

Let's point to the stuff I'm familiar enough with to have done personally: stage combat. Someone does a play with a fight scene. Actors that do stage work tend to pick up the very specific skills involved in making a fight scene in stage look "real enough". You don't have to learn how to fence for real, you just have to look interesting while you clash fake swords together.

That goes for hand to hand scenes as well. Matter of fact, in both cases, you'll often be training how to miss and still look like you hit. This means that an actor that doesn't train outside of stage combat is going to have trouble in a real fight because their reflexes and perception of range aren't going to work right.

Movie fighting can be exactly the same. The actors aren't supposed to hit each other at all. Fight scenes are planned ahead of time, with camera angles set so that the shoot is reasonably safe, but the action looks good on screen.

So, again, most movies or shows aren't going to be training actors to actually fight. They may not even do amy marital arts training at all, even just to look a little more realistic, because it's faster and cheaper to have an actor just memorize steps like in a dance. Which isn't too far off from what kata are tbh. So an actor in that kind of production isn't going to gain any practical skills at all.

However, some productions do have the actors train to some degree or another because it allows for a little improv and for the actors to move like they know how to fight both within a fight scene and in other scenes.

That productions sometimes end up with actors having a degree of real proficiency in what they're taught. However, it's very rare for a movie to have the budget for that. Even the Matrix and John Wick didn't go super deep into it. They hired top end stunt performers and choreographers that prepped the actors extremely well. The Matrix in particular was a lot of wire work, really heavily influenced by Hong Kong style kung fu movies. So they didn't teach the actors any significant fight skills, more how to look like they knew how to do stage/movie kung fu.

Now, Keanu is actually a really great example to use. He's got a reputation for putting his work in outside of what's required. He's done a shit ton of firearms work over the years on his own. And, supposedly, he has done some h2h training too, though I've heard conflicting stories about what kind.

And there's been plenty of actors that have a background in some variety of fighting art. Plenty of actors end up finding a love for one style or another from acting. Fencing ends up being fairly popular among stage actors, though they rarely compete, and never seriously that I've ever heard of.

But could Keanu do the same things as in the movies? Hell no. Dude is human, and doesn't have an entire team supporting him in a real fight. Nobody could pull off the stuff John Wick does because he has plot armor. He's going to get hurt, but not catch a stray bullet in the head and drop dead.

Could Keanu hold his own in a realistic fight? Probably. He's physically fit, has done at least a little training, and those two things are huge advantages in a random fight with some asshole looking for trouble. Could he step into an MMA gym and hold his own with fighters his own weight class and age range? I don't know. Maybe, like I said, he stays in good shape, so he wouldn't be an utter failure.

But it depends on how much work he puts in on his own time. A year of training for a movie isn't going to mean shit if that's all the training you ever do, no matter how good the training is. Fighting is one of those things where you will lose your skills to some degree if you don't practice in some way. I've lost a good bit of ability over the years since I can't train the way I used to. I can't take falls, I can't move the same, so if I was to jump on the mat and try to roll, I'm likely going to need a doctor. I might, however, be able to fake it on camera with a little help.

But I have had violent encounters since becoming disabled, and that's not the same as sparring with someone trained in controlled settings. So I did fine. Came out of it uninjured entirely in every case, though I felt like I'd been beat to hell because my body just ain't what it used to be. So I wouldn't count an actor entirely as untrained if they were dealing with a low threat fight over a parking spot or whatever.

So, there's no single answer here. In some cases it's a hell no, they're toast; in others it's where I'm not likely to start a fight with them