Reddit comes to mind. Who knows how much money they spent on their redesign with users hating it and actively choosing to use their old site design YEARS after they rolled out their new design.

I also run a site and when I ask people what I should improve next, nearly no one says design, even when the design is clearly not very good.

An example of a site that never changes is Craigslist. I can't even recall the last time it looked different. It's probably overdue for a redesign even.