Why do people think that WWE owns copyright wrestler's gear?

I think WWE own The Fiend's gear. I remember hearing that Wyatt wouldn't be able to use that attire in another promotion. 

WWE have also released Fiend merch since his release which kinda confirms it.

I agree with what you're saying. Plus, WWE doesn't renew all of the branding/characterization they have created over the years. Pretty clear that Bryan Clark owns Adam Bomb now. Seems like it's case-by-case. Pretty sure Bret owns the Hart Foundation logo. So PWTs is making Hart Foundation branded items that those guys only wore on WWF TV, at least to my knowledge. Just reaffirms what you're saying. WWE can own a character or logo, but they can't own a character forever unless it's trademarked correctly and then maintained. NWO, DX, Razor, Diesel, sure, but there is likely a plethora of trademarks they've let expire for various reasons.

I think WWE assumes/or projects that they own a lot of things they don't actually own, so fans do the same, and they've got a big scary legal team to push people around. They sent the Young Bucks a C&D over the too sweet, which they didn't even own. I think PWTs has given guys a reason to go and get the copyrights they're associated with if WWE isn't using them. I love seeing that kind of stuff. Chella and Zombie seem to be doing their due diligence. Zombie is making like a Mania 6 era Andre and it's totally separate from any of WWE's licensing. So yeah, I think we're sort of seeing this WWE owns everything illusion exposed.

The biggest problem is people really oversimplify the trademark / copyright issue.

There’s a reason there’s lawyers who specialise in aspects of copyright and trademark law.

Along with this things like logos, names etc there’s also image rights and that an include along with a persons likeness “recognisable characteristics”

For someone like say sid, plain trunks and boots isn’t really all that recognisable - however we can all probably think of 10 wrestlers off the top of our head who’s attires you could immediately relate to being them. Think of it like this: take away the bat sign (which is obviously trademarked) and have someone in a grey Lycra suit, blue boots, mask, cape and trunks over the top of the suit and a blue mask covering the top half of the head people would recognise that as adam west era Batman. There’s some superhero outfits mattel have fo even the past when they also had rights to the relevant superhero line but not really since - I mean they did they ‘silver surfer’ Rey but most people wouldn’t realise it’s silver surfer inspired. It just looks like they forgot to paint it lol.

Then there’s also the weighing up of potential costs and legal issues v what the figure brings to he line. If there’s any possibility of potential headache I’d imagine a company like mattel would just stay away. Why bother considering a figure, going through the manufacturing process only for it to be pulled as soon as it hits shelves and then sit in a warehouse while it’s being sorted - they’ll just do another attire

I think as long as they didn’t create the character they should be fine. I don’t see how Owen’s gear would be owned by WWE unless it has specific WWE logos or they made the gimmick. There’s certain guidelines that allow certain interpretations/inspiration to be held without infringing intellectual rights. Look at Shepard Fairey, he won a lawsuit against him if I’m not mistaken.

I've heard Hall and Nash say in shoots that they tried to get the seamstresses from wwf to jump to wcw.

I could see that having something to do with it. If wwf/wwe employees are making the gear, I'd imagine they have some claim to it.

Then you have someone like Macho Man who paid someone himself (and spent a ton according to some accounts) to make a lot of his attires, so I would think he (his estate) owns that stuff.

Just guessing but this is something I've wondered too..

Same. I don’t see any issues with the pink and black Owen attires unless it’s something like the slammy attire etc. I remember someone saying that we wouldn’t be able to get WCW Sting which is not true. WWE does not own his likeness. The only thing we wouldn’t be able to get is a Sting with a nWo logo, which is fine because he wore plenty Wolfpac attires without it.

I mean it really can’t be confirmed without delving into the copyrights and trademarks. I just know it’s not something I’d be willing to test with my own investment seeing as they definitely do own the footage. Copyright is still a relatively new concept legally, which is why I’m saying it’s messy.

I just want the Jazwares Owen to not stand out like a sore thumb standing next to Mattel's HF Bret, Bulldog, Neidhart and Pillman.

There can be many things that can be owned/trademarked by someone or a company. I remember reading years ago that the WWF sued Scott Hall after he signed with WCW, they said his Scott Hall character was too similar to the Razor Ramon character that they (WWF) created. They complained about his slicked-back hair, the toothpick, the Cuban accent, and ring attire (vest, trunks, etc.) Apparently, as a result of the trial, there was an agreement that Scott wouldn't have anything to do with razors on his tights/ring attire, gold chains, and would dial back the Cuban accent. But Hall could keep the slicked-back hair, toothpick, and other mannerisms that were similar to Razor Ramon because he used those things as the Diamond Studd. It's strange. A lot of guys prior to 1990 owned their own character's name and look because they wrestled under that name, and wore the attire, prior to coming to the WWF. Also, prior to the 90s, it appears guys tended to pay out of pocket for their gear/ring attire. After 1990, it seems like the WWF started to create characters for their performers, gave them new names and designed their look/attire, so they copyrighted those things so a performer couldn't become famous with the WWF then go somewhere else and capitalize on the character that the WWF "created". Bruce Prichard talked about this on one of his podcasts, the WWF has to keep paying each year to keep the copyright, after some time, the company decides if the copyright is worth keeping or not, if they think it isn't they don't re-up the copyright and someone else can pay to own the rights. I believe this is how some wrestlers, like Bryan Clarke, are now able to own their old wrestler's name and likeness - the WWF just didn't think the copyright was worth paying for anymore.