Ok..

all of the 5 inventions are not as complicated as cell fones, TVs for example.

TVs & cell fones required big number of prescribed steps. Those complicated items require careful design and humans intervention. this big number of steps in an orderly manner cannot happen by fluke.

I agree that the 5 inventiontion you quoted were fluke. However, it took further work, by humans to make them usable. Those inventions were not merely a fluke.

Regarding Pencillin, the following is an excerpt from an article:

(Though Fleming discovered penicillin, it took Florey and Chain to make it a usable product.)

Full article at:

http://history1900s.about.com/od/medicaladvancesissues/a/penicillin.htm
http://history1900s.about.com/od/medicaladvancesissues/a/penicillin.htm