Rock quick move doesn't change Tyranitar's counters at all, it's a bad defender due to the double weakness and raid bosses won't have the move anyway.
As for gen 4, Lucario and Gallade have the attack stat to challenge Machamp, but neither can learn C/DP. There's of course a possibility of an even better move than DP but that seems unlikely. Lucario is also so glassy that it likely won't be useful, even with its steel typing it's still glassier against psychic and fairy than Machamp is.
Gen 5 is when Machamp and Hariyama get outclassed by both the non-legendary Conkeldurr and possibly some legendaries as well.