I love this example. Thanks for sharing! It's very encouraging to remind me to just make something and get it out there.

One prominent counterexample that comes to mind is Friendster which was a big social network before MySpace and Facebook. They had terrible performance issues but to be fair to your point, their decline was more mismanagement than a true inability to scale.

https://www.inc.com/magazine/20070601/features-how-to-kill-a...

https://en.wikipedia.org/wiki/Friendster