More fundamentally, evaluating HCI research is very subjective. That means it's harder for a diverse audience to even agree on what constitutes good HCI research. Many HCI researchers have grown frustrated with the value of their research being discarded or overlooked by review committees. As a result, they tend to favor lowering the bar to entry, and accepting more papers, thinking that it's better to have false positives than false negatives.
Prices are alright for identifying interesting talks at a conference, but you shouldn't compare them between fields.