Templates were a problem but not a huge one. They aren't used extensively in the webserver, and in any case they bloat compile-time moreso than link-time.
The bigger problem was that we'd adopted a dependency strategy of "lots of little libraries" instead of "one big library with lots of source files". This offloads a lot of the work from the compiler to the linker. There are various advantages of this strategy - it speeds up incremental rebuilds, it encourages you to explicitly track all your dependencies, it simplifies IWYU, it's easier to parallelize - but linker RAM usage is not one of these advantages.
The bigger problem was that we'd adopted a dependency strategy of "lots of little libraries" instead of "one big library with lots of source files". This offloads a lot of the work from the compiler to the linker. There are various advantages of this strategy - it speeds up incremental rebuilds, it encourages you to explicitly track all your dependencies, it simplifies IWYU, it's easier to parallelize - but linker RAM usage is not one of these advantages.