There's a generational shift going on here. That's why the anti-gun backlash "feels different" this time. It may or may not have any different immediate results, but it's the trend for the foreseeable future.
Despite all the talk about the Founding Fathers, there's an aspect of the present gun control issue in the U.S. that's largely rooted in 20th century European and Asian history; specifically, its genocides of relatively unarmed populations. My father's generation was acutely aware of it; many of the immigrants of that generation and the previous one came to the U.S. to flee it. That represented, not necessarily a bloc of gun owners or enthusiasts, but people on the sidelines of that generation and the next, who felt they had, and in some cases still feel they have, an adequate reason to accept the costs and risks of having a well-armed citizenry.
A case in point: the only firearm my own father ever owned was a collector's piece that he inherited late in his life, and he kept it disassembled and never attempted to fire it. Yet I heard him say this, more than once: "If every Jew in Europe had met the Gestapo at the front door with a gun in his hand..."
He didn't finish that sentence. The implication was that the extremes of the Holocaust might have been prevented, although surely such armed resistance would still have been suicidal and there would still have been a bloodbath of some sort. But then, it's plausible that if such a massacre occurred in one neighborhood, the next neighborhood due to be visited might organize a more effective form of armed resistance. As people have pointed out in this thread, such resistance wouldn't be effective in a straight battle against a country's armed forces, but in this case, and as will often be the case in such times of civil upheaval, those forces were busy elsewhere. Ultimately, a genocide (or invasion, occupation, coup, etc.) might be made too costly to sustain, or to contemplate in the first place.
Now we’re seeing a generational shift. To the kids in the Marjory Stoneman Douglas High School, the menace of NKVD or Gestapo agents with uniforms and pistols pounding on every front door on your block in the middle of the night is nearly as historically remote as the menace of Napoleon’s armies marching in formation across your farms with muskets and cavalry would have been to my parents’ generation. Understandably, they see instead the risks and costs of an armed citizenry, that have played out right before their eyes.
Sooner or later it will be their choice to make. All we can do is help make sure they have the knowledge to make that choice an informed one.