The point is that it works 95% of the time, or probably more like 98%.
If this is a e.g. webserver and I only need my fastcgi backend built by myself, I can still have reverse proxy, database, and every other package be done by the distro.
No one said you need backports. More like: If it fits 90% and one package doesn't work, you get it from somewhere else - that doesn't invalidate the concept of a distro for me. YMMV
