It's great that you can find examples if you search hard enough. Thing is, it's just too few and far-between compared to Marvel doing it all the time. Those examples I listed? Just off the top of my head.
Here are some more:
- Blackheart debuted in a Daredevil comic, but more commonly fights Ghost Rider nowadays. He also pops up in X-Men every now and again.
- Cloak and Dagger's most recent run had Spidey rogue Mr. Negative as the main villain.
- Baron Helmut Zemo debuted as an antagonist to Captain America and Falcon (under the name of the Phoenix). Since becoming the Baron, he's become a general Avengers villain, and then a villain to the Thunderbolts he founded, in particular the replacement leader Hawkeye. Recently, he's menaced the Punisher.
- Madame Masque has historically been an Iron Man villain, but since Fraction's Hawkeye run, has become the nemesis to Kate Bishop.
- The Absorbing Man was and still is a Thor villain, but has tangled with Hulk a lot of the time as well.
- Beetle (Abe Jenkins) was originally a villain to the Fantastic Four (in particular, the Human Torch). He's been an Avengers villain as part of the Masters of Evil, and a fairly regular Spider-Man villain, as well as an occasional Iron Man villain, until he permanently became a good guy as MACH after realizing that being a hero was better in the Thunderbolts.
- Spider-Man's recent Nick Spencer run had him fighting the Thieves' Guild, who usually are exclusive to the X-Men titles (debuting in the Gambit series).
- The Phoenix Force is a major entity in the X-Men comics, and became the driving force of Avengers vs. X-Men. It then migrated over to the Thor titles, having a history with Asgard.
- Alex Wilder was the secret villain of the Runaways, and since coming back to life he antagonized Power Man and Iron Fist.
- Taskmaster debuted in the Avengers, and though he's an Avengers foe, he also antagonizes members individually such as Captain America, Iron Man, Hawkeye, Ant-Man, as well as others like Spider-Man, Spider-Woman, and Daredevil. Heck, he's even had some presence in X-titles, with his longstanding rivalry with Deadpool, and has fought Wolverine, X-23 and Daken. It helps that he's a mercenary for hire, and will fight anyone if he gets paid.
- Deathbird, like Mystique, was a Ms. Marvel villain who migrated to the X-books.
- Mojo and Spiral were and still are antagonists to Longshot, but during his miniseries it was completely disconnected from X-Men until Claremont brought Longshot over afterwards, and thus those two as well, making them X-Men villains.
- The Purple Man was a minor Daredevil villain who eventually became the core archenemy of Jessica Jones.
- Annihilus is a longstanding Fantastic Four villain, but was the main villain of Annihilation where he fought all the cosmic heroes and the ultimate villain for Nova to defeat.
In general, when Marvel introduces a new hero or promotes one from general obscurity, their rogues will be adopted from elsewhere (likely unused at the moment) with a few new ones. I think it works well, as DC often makes up new villains in their case, and rarely are they memorable nor have any impact.
I think it might be reason of tone. DC prides itself in having many smaller settings that fit a different niche, while Marvel is much more connected and lets it all flow together. I mentioned there never being a Wonder Woman comic where she fought Reverse-Flash, and it's easy to figure out why: Wonder Woman is based on Greek mythology and high fantasy, while Reverse-Flash is from the future and has a sci-fi origin, which would make him stick out like a sore thumb. DC is a kitchen sink of science and fantasy, but wants to make sure each side is distinct when possible. Sure, Marvel is
also a kitchen sink of science and fantasy, but they never had much of an issue with the idea of Iron Man (an industrialist billionaire playboy in a suit of futuristic power armor) fighting Loki (the Norse God of Mischief) so long as they thought it made a great story.
That's how I see it, anyways.