We sponsor Matz, Nobu, and Koichi. Of them Koichi works pretty much full time on speed. He implemented partial generational GC in Ruby 2.1 and incremental GC in 2.2. He also implemented faster keyword arguments https://bugs.ruby-lang.org/issues/10440.

There's actually been a bunch of great performance increases in the past few years in addition to the GC. Optimized method cache invalidation by the late James Golick, frozen string pool for hash keys by tmm1, using vfork instead of fork, etc, copy on write GC. There's also new features, like Ruby's ability to GC symbols that let developers use symbols in more places and spend less time converting back and forth between strings.

So yes, money is a factor. Having employees work on it full time helps. Despite only having 3 full time employees Ruby has made some pretty impressive improvements recently.