I don't know about "eliminating" anything -- all their songs evolve and change over time. When they first changed Echo they described it as a "boot scootin' rhythym" or something. How many different ways will they play so/slow ready? They "eliminate" things until they bring them back (See: Myst)

I mean it’s pretty clear that the Echo and AIN second jams have been eliminated over the course of arrangement changes and Drive’s is basically gone as well