Why did a famous mathematician say that algebraic topology was dead?
Solution 1:
Novikov was mentioned in the comments as a possible source. Some of his views and memories are published in the article
http://arxiv.org/abs/math-ph/0004012
He calls 1970-80 a "period of decay" for topology, naming the following problems: migration of leaders to other fields; a relaxation of rigor and standards of documentation; the resulting "informational mess" about what had been proved and by whom.