The original Batman retired in DC Super-Stars 17, from 1977, and died in Adventure Comics #462, in 1979. He never came back to life or anything, though according to the wiki he did once appear as a spirit in JSA #82 in 2006.
To be clear, the current Batman is not the original, but a multiversal doppelganger of the original, and technically his first appearance is considered to be in Superman #76, from 1952, which is said to be the first time Superman and Batman teamed up, which means they were never in the Justice Society, which means this must be a different Batman (and Superman) than the original versions, which were in the Justice Society. Also note that this second Batman's history from before Superman #76 is considered to be very similar to the original Batman's history up to that point, just without particular differences, such as the aforementioned Justice Society thing, and the fact that the original Batman (and his whole universe) seemed to move more in real time, while the second (current) Batman operates on a sliding timescale, so he ages much more slowly and is much younger than the original.
While I'm at it, I should also note that that second Batman I mentioned, though technically the current one, has had aspects of his history altered a few times, most notably after the Crisis on Infinite Earths. However, he is still technically the same guy, but history changed around him. Batman has generally had his history changed less than other major characters, though. Also, while the original Batman was from Earth-Two, and there is another universe called Earth-2 and later Earth 2, that is technically a different universe entirely, created by Alexander Luthor, Jr. in 2006. Earth-2 had a history very close to Earth-Two, and its Batman was already dead, but the point is that it still wasn't actually the same as Earth-Two. After the Flashpoint, Earth-2 had its history drastically changed, and the Post-Flashpoint universes drop the hyphen to make it slightly easier to identify them, so from there, we'll call it Earth 2. Earth 2's history was drastically different from Earth-Two, but did feature doppelgangers of people who were well known for being from Earth-Two. Still, it was technically not the same universe, and also was really different anyway.
Also, in 2015 Brainiac of Earth-0, who had escaped the Flashpoint and then absorbed Crisis Energy and became super powerful, went throughout time and grabbed cities from various notable moments throughout the multiverse, such as the moment before a universe got destroyed, and brought them to the present. Then he turned all these cities back into whole universes, including Earth-Two right before it was destroyed in 1986. Then he sent a few characters back in time to make sure that places that were about to be destroyed won't be destroyed anymore. So technically there is a splinter timeline/universe of Earth-Two that currently exists (though note that it's outside the "local multiverse" so it's harder to reach from the main universe), however, this is still just an alternate timeline/universe that splintered off of the real Earth-Two, which was still folded on top of Earth-One to become New Earth in 1986. Also, Batman of Earth-Two was dead well before 1986 anyway, so the Batman of the new Earth-Two is also dead.
With Batman out of the way, I'll also mention that the original Superman retired in 1986 and died in 2006. He briefly came back to life as a zombie in Blackest Night in 2009, but so did everyone else who ever died. The original Wonder Woman also retired in 1986 and then left reality in 2006. All my explanation for why the current versions and the Earth 2 versions and New Earth-Two versions aren't the originals still applies here.
I mention those three because they're among the most famous characters ever. Of course, it applies to many others as well. The more obscure, the less likely it is that they'll get brought back to life. There are plenty of Justice Society characters who died and stayed dead. The first two Blue Beetles (Dan Garret and Dan Garrett) died and stayed dead, and while the third one (Ted Kord) currently has some sort of Post-Flashpoint rebooted version running around, note that the pre-Flashpoint version's story ended completely, and the pre-Flashpoint version of his best friend, Booster Gold, is still around (as the current Waverider), as a distinct character from the Post-Flashpoint Booster Gold, so for Booster and characters close to him, especially those who were heavily altered, like Ted Kord, they really are completely separate characters.
A similar case is with the original Supergirl. Kara Zor-El died in 1986. History was then altered so that she "never existed," but really she did, but people didn't remember her. A new Supergirl, Matrix, debuted in 1988, but while she is called Supergirl, she has an entirely different story. She is not the same character. Later, Kara's ghost would appear a few times, and they would say there was some fucked up multiverse shit that was preventing her from being rebooted into the new history, but they solved it, and then she was rebooted into the new history. So technically the Kara Zor-El of New Earth is the same soul as the Kara Zor-El of Earth-One, but they have entirely separate, though similar, stories. Kara of Earth-One's story completely ended and then Kara of New Earth's story began. She would then be fully rebooted again after Flashpoint. Technically the same person, but really, it's a completely new story, that begins from the beginning and counts no elements from the old version as canon (though many current elements are shared with the old version).
>tl;dr: Lots of characters died for real and stayed dead. The simplest examples are the original Batman and Superman. Go read those if you want.