alt Hacker News"Linker"?
In theory, the motivation for position independent code was to support the development and use of software libraries that could be "plugged in" to an application.
In practice, RAM was often limited to 16 KB; software reuse that I'm familiar with on a 6809 platform was at the source-code level and optimized by the programmer.
I remember editing and assembling, but not compiling or linking.
That said, I believe Motorola wrote some floating-point libraries.
I was a kid on a Tandy Color Computer, and the $49.95 EDTASM cartridge was a huge investment for our family. So my point of view could be way off... but the simplicity of the Color Computer with the design of the 6809 made programming delightful. (20 years later, my enjoyment in programming the Palm Pilot felt like that... although by then I could use C as a fancy macro assembler.)
Larger and later systems could use OS-9, which reasonably resembled UNIX and maybe supported a C compiler.
I believe that linking became important when programs got too big to compile within the memory limits of the computer. Then you had to compile portions of the code into separate object files, and then "link" those object files by reconciling the identifiers with their addresses. Without having to haul everything back into the compiler at once. It also meant that portions of a program didn't have to be recompiled if they weren't ever changed.
This wasn't the only way to skin the cat. Multi-pass compilers were another way.
Relocatable code could make more efficient use of memory, for instance not having to worry that your object code would end up crossing a page boundary after linkage.