Social media is a perfect example of how "liking" something does not increase comments. Look at any builds posted by the huge amount of tech orientated users. You can have thousands of likes on something with only a few hundred comments. Most of which will be users tagging other users.
I agree that having any form of "Kudos" on forums can be useful, especially when it comes to stroking egos. However I am very old school and believe in active participation in forums, in that respect, Post count is often a valid representation of active and genuine members.