Of course there are other interpretations. Maybe the Jews had different interpretations at different times. I'm sure that's possible.
During the Roman occupation, it's pretty well established that they were looking for the messiah as someone who would lead them to liberation, which is more than indicative that they were looking for a person, a leader.
Isn't that true of all times? Aren't all of us looking for a leader today? But is that what is meant by Isiah 53? According to the writer, there seems to be only one possible explanation. But he's mistaken. There are others.