Nodes store 2 things. Block headers, and UTXOs indexed by outpoint. The contents of any script is not their concern until they must load the outpoint in order to spend it, which they look up by the outpoint, which is what a tx input points to. 

I'm not implying that addresses are going away, though who knows what scripts will emerge, but once addresses are rarely re-used, then the value of an per-address index may not be worth the cost of maintaining said index.