I have needed ambulance care a few times. The paramedics/EMTs (we don't have a separation like that in my country, we just call them ambulance nurses: a nurse who then specialized in doing "solo" emergency care) were always helpful: it varied from saving my life, having a good/comforting conversation during a "taxi trip" (psychiatric transfer), making me as physically comfortable as possible during a "taxi trip" (somatic transfer, from the hospital to amputation rehab), checking me over after I fell and hit my head very hard, monitoring me when I passed out and wasn't waking up..
They always were an oasis of rest even when everyone was panicking. EMTs "break through" the bystander effect by knowing what to do, acting on that knowledge, and ordering bystanders how to help, if that's needed.

I can't speak against to your experiences. Just wanted to let you know that to me, you are noticed and appreciated. And you do make a difference even when it doesn't appear that way.