Strange, I was always under the impression that hdtv:s and players lacked DVI ports because it didn't comply with hdcp.
DVI-A (analog) didn't have support for HDCP, but analog only DVI was extremely rare, DVI-I and DVI-D always had it.
Biggest differences are, as already mentioned, audio support and that DVI is RGB only, whilst HDMI had YCbCr support from get go. Back then that really didn't matter, and later on display-port replaced DVI, so YCbCr, xvYCC, etc support was never added to DVI.
Display-port also supports HDCP.