While there may be good apps, I tend to define "Killer App" as a specific program that people not already in the ecosystem will explicitly buy into a hardware platform to run. The classic being VisiCalc for the Apple II and Lotus 1-2-3 for the IBM PC. On the gaming side, think about how many millions of Game Boys were sold so people could play Tetris; one suspects a significant number never saw another cartridge in their life. Or, perhaps less hyperbolically, Halo got a lot of people onto the Xbox platform, and FF7 did the same for the Playstation.

Does any VR title have the same degree of wide awareness and demand those programs had at their peak?

I could imagine someone trying to force the hand by moving a beloved franchise into VR-- imagine if the next Dragon Quest was VR-only, for example, and people who buy everything with that cute blue slime on it would also buy cute-blue-slime shape headsets. Meta has the resources to buy such a situation into existence, but it might not be what they're after because it's likely to still be only a narrow draw-- they're used to building a platform for All The People, not just the audience who followed a single beloved franchise over.