[gnufx]

Exactly, but even if you can rebuild it, you don't want to under most circumstances. In principle with static binaries you can use dyninst, for instance, but in practice you may not be able to for various reasons. Then as a system manager you'd like to have global profiling of what runs -- for various reasons, including putting the result for a program in front of a user. If it's all dynamically linked, you can hook in and do that by default, and with various levels of insistence, depending on the hooks.