The Hastings brothers (who were actually down the hall from us when we were writing Crash) are really awesome coders. Even so, however, I don't think Spyro for PS1 actually had anywhere near Crash's effective polygon count. Crash himself was over 750 polygons, which was not bad for an entire frame of a PS 1 game.

According to this great series on the making of Crash Bandicoot¹, Spyro used walls to reduce the number of polygons visible concurrently.

¹ http://all-things-andy-gavin.com/2011/02/02/making-crash-ban...

Quake 1 did that too