There are a number of factors at play here. One is that in most cases big battles of the sorts tanks excel in aren't fought that often. The other being that there is little media coverage for when they are used in most unspectacular, low key but important roles so it creates the perception that they aren't used or are important.
They are. Just because big tank battles a la WW2 aren't fought anymore it doesn't mean they aren't there, doing their role.