The C compiler on HP-UX was an extra cost item and it wasn't cheap. Porting programs to HP-UX often required some tricky changes because the C compiler wasn't as mature as GCC on x-64 systems of the time.

I recall that once Oracle acquired Sun, they gave priority to getting latest releases of Oracle RDBMS and JVM running on Sparc before HP-UX and AIX. In the corporate space Oracle and JVM were pretty much the main game.