If you take your hypothesis for example, it may explain the explosion (rapidity) of the evolution of new species but it still doesn't offer viable reasons why the explosion was isolated to that period only.
(Just an amusing side note: my God-believing and evolution-denying BIL uses the evidence of the Cambrian explosion to suggest that no scientist can explain why there was an explosion of diverse species is such a short time - it had to be "God's hand". "Only a creator can do such a thing". I must admit, until the arrival of my BIL, the Cambrian period was of mild interest to me. I now read about it with "special interest".
Cheers!