There is most probably no other explanation to 29. ... Bxh2 than this that Fischer made an experiment with Spassky in so far that he just tried to find out how far he could go with his opponent. One source said that he claimed to win over any Russian even with the handicap of two or three points behind.

Another author compared him to a brightly shining comet in the chess sky, overshining any other star up there, an event that will never be repeated again. Only now, when looking back decades later, people start to realize what they had when he was amoung them.

Regards!