Some examples that come to mind:
Seems the sales are mostly fine.
Add Team Fortress 2 to that list.
Announced in 1998 and released in 2007.
I don't have firm numbers for it, since it is F2P.
44 million owners on Steam, and updates over ten years after release: is a success to me.
The game also came out on the Xbox 360 and PS3 via The Orange Box.
Star Citizen has "sold" over 1.9 million units (1.9 million backers) as of right now.
Almost 176 million USD raised via crowd funding.
Also still in development:
Dwarf Fortress, has been in development for over 15 years now.
No release date is in sight.