Well on Slackware, you can remove the package manager and all the packages, replace it with pkgsrc, reinstall everything and it works fine. Of course, the coreutils, kernel, important system programs, init system and all that don't come with pkgsrc, all of the actually interesting stuff will be left to us to implement. I think it's really important we don't get a case of NIH and try to make everything ourselves for no concrete reason and for no benefit.