Is Generations that old already?  When you've been gaming since the 1985, PS3 seems like only a couple of years ago!

By the book horse blinders reply.

It is basically brand suicide to allow others to use your intellectual property. Not just from a perception angle, but from a legal angle.

Legally, if you don’t defend your trademarks from unlicensed usage, you lose them. Nintendo probably has FAR higher licensing standards than Sega and product goals; Nintendo is not going to hand it out to some random fan the way Sega would (assuming this is true) for free. Especially since Nintendo has extensive liscensing deals with their characters to other companies who must adhere to their standards.

I am sorry, but people who are defending unpermitted use of someone else’s trademarks and intellectual property are profoundly ignorant. I don’t mean that as an insult, I mean that as a statement of fact: get out there and educate yourself on trademark law, fair usage, and licensing practices. These laws exist NOT to be oppressive, but so that content creators and their business partners can actually own their intellectual property. It would be dumb if Microsoft or Apple were allowed to go out and make Zelda, Final Fantasy, and Mario games without Nintendo’s authorization: how is it that people can’t see that?

I would guess Nintendo have an image to protect as well so they don't want clones of pokemon around the place but where you collect pictures of Hentai instead of the pokemon... I mean, we already have Lopunny what more do people want?

More like a mature/adult reply based on personal experience working as a product developer, thus knowing how much time and energy is put into making IP.  Some of my patents took years, literally years to develop.  And no, somebody can't just take it because reasons.  If people can just hijack IP, then it defeats the purpose of companies spending the time and money in the first place.  And we don't want a market where companies are not driven to develop IP.  Anybody who believes IP should be up for grabs clearly has zero experience in the real world.  

If you have enough talent to make your own game then create your own assets. If you want to make fan based game regardless then share it with friends or closed off group. Don't expect to just drop it everywhere on net and get all butt hurt when it's taken down. Is it that complicated?

Square Enix do it they did it with a fan made remake of Chrono Trigger, Activision did it to a Spyro project not long ago even Sega who people try to praise in this regard do it quite often as shown with the SOR project that got shut down. Other examples are Konami shutting down the MGS fan project after they changed their mind on it being okay mind you and the Vampire the Masquerade remake getting stopped even though the developer had gone under.

https://en.wikipedia.org/wiki/Chrono_Resurrection

https://www.techspot.com/news/76627-fan-made-spyro-game-hit-cease-desist-letter.html

https://www.wired.co.uk/article/sega-shuts-down-streets-of-rage-remake

https://www.rockpapershotgun.com/2014/11/24/vampire-the-masquerade-bloodlines-remake-cancelled/

"Fan games"?
Or using anothers brand to gain popularity?

That has probably some thing to do with the fact that most of these  fangames are games from the 8/16 bit era, where Nintendo reigned supreme and had the most recognizable IPs these days.

Sega for instance killed remakes of Bare Knuckles (Streets of Rage) shortly after supporting the developers, probably for the same reason that Nintendo does it: It's lawyers told them that they need to protect their IP, as IP laws make no distinction between copying an IP for profit or as an hommage.

Zero tolerance is pushing it too far: If it's gonna be free and in a creative way (so not just copying the game), they're often okay with it. Just look at Abobo's Big Adventure or Super Mario Crossover for instance. Or all those Kaizo Marios