Takahashi sure does love time-travel isekai.
I wonder what it means.
At the time the Inuyasha manga released, sure, Shoujo genre isekai was popular. But Escaflowne, Fushigi Yuugi, and Magic Knight Rayearth all transported the heroines to fantasy worlds. (My understanding is that Fushigi Yuugi's setting was a fictional version of ancient China.) If Takahashi was just told to ride the trend at the time, wouldn't she have chosen a fantasy world for Kagome to travel to? Instead, she went into the past. I think Takahashi has a particular interest in travelling to the past, specifically. Interesting.
Maybe it has to do with how each of the protagonists who travel back in time, actually have their roots in that past time period. Kagome was a reincarnation of Kikyo. Suzu actually is from the past. I didn't read Mao yet, but I wouldn't be surprised if the protagonist turns out to "actually belong" in the past.