Sadly, it seems people are thinking the part of "Disk space is cheap"; so why bother separating things apart. Even on Linux, lately it has been becoming more of a requirement that everything has to be on the same disk (logically or physically). Like you use to be able to have /usr on a separate disk/partition but now you are required to have it on the root drive to even boot.
Anymore, I prefer Freebsd's way on organizing stuff; especially on a clear division on what is the core and what is more of an additional "add-on".