And so was I. M48 tanks in Vietnam used the same rubber track blocks they did in FT Knox. I don’t know when the US stopped using steel track, but I guarantee you it was before they started using me in 1964. The large rubber tread on the track blocks provided better traction than flatter steel tread. It also weighed much less.
IIIRC it started with the old M-3 Lee tanks having rubber tracks.