Why?

probly trying to do both angles , the teens wont mind that some show in the 80s had the same name


Theres no mention of the bounty hunter part though , so sounds like a totally different story.

I don't get the sense this is meant to be related to the old TV show. Whatever it's meant to be, it looks excellent in the trailer, and Gosling pretty much never makes a bad film.

The same thing can be say to every movie that is adapt from books.

Why use the title from the book? Not many people read the book they adapted.

The main reason is that Universal thinks it has the prospect of becoming a big $$$ franchise like Mission Impossible.

I expect a theme park ride if it's a hit.

Bc they didn't get around to doing Six Million Dollar Man

The real reason will be The Fall Guy movie has no doubt been in development hell for about 20years (along with movie versions for other 80s action series Knight Rider, Airwolf, Magnum PI, TJ Hooker etc) back when it would've been ripe for mainstream nostalgia but bc The A Team bombed in 2010 and whatever other reasons it didn't get done until now for reasons unknown (probably the John Wick director and Gosling are big fans of the show and had an opportunity to do it)
Edit: the director talks about his love of the series here https://www.empireonline.com/movies/features/the-fall-guy-trailer-breakdown-director-david-leitch-and-producer-kelly-mccormick-on-stunts-stars-and/

Does it need to be based on the original Fall Guy? No, not at all. The Fall Guy was a typical 80s American action procedural, where a small group of misfits "help" upholding the law. It was a nice way to bring in cameos made on Universal backlot, but still quite underutilized, because of course they couldn't do back then a big stunt men show on a TV budget.
But it could work also well today, stunt persons are fascinating people, who put their life in danger. Why not making a premise out of it? Drive did this imo quite well, that's why I thought that Ryan Gosling is a good choice. Of course it shouldn't be SO grim, but more concentrated on the live of a normal stunt person. We could even have the forced into bounty hunting in, because thanks to CGI stunt persons are not so much needed anymore.
But the trailer makes it look like Colt Seavers is basically Ken after 5 years in the real world. The hotel room scene is just totally out of character for a stunt person, who saw already a lot of shit happening. I hope the movie will be better as what the trailer currently offer.

Maybe the IP is expiring... wasn't there something about brands/trademarks expiring when they're not actively used for some 20-30 years?

Thought the same thing when they made that C.H.I.P.S. movie.