There will be a lot more example of this in the coming years because the costs of keeping a pre-PMF webapp online have basically fallen to zero. Whereas when Zuckerberg started Facebook, if it didn't take off right away then you had no choice but to shut it down.
When you hear VCs and other folks cast doubt on the ability of anything that doesn't immediately capture lightning in a bottle to succeed in the long term, they are incorrectly pattern matching to a trend from the past that just happened to be an artifact of the economics of that time period.