My first real road bike was a Giant TCR Alliance, where the top tube and the top part of the stays were carbon. It felt very good to me for the price, but yes, they haven't done that for a few years. I'm with the theory that that price point was just taken over by pure carbon frames, which have gotten cheaper over the years. The bonding process can't be free.

I was worried about the bonding locations, but they were solid for the year+ I rode it, and stayed solid even after I crashed it hard enough to break my pelvis.