As many of you know, there is a website, including video, making the rounds proving that strawberries are infested with a "new" insect called thrips.
1) Thrips have been abundant for well over 100 million years http://en.wikipedia.org/wiki/Thysanoptera#Evolution_and_systematics
2) A quick review of the agricultural literature reveals that thrips infestation of straweberries is most definitely not new, here's just one of many examples: http://ohioline.osu.edu/rc299/rc299_9.html
3) R. Moshe Feinstein argues that any insect that is not clearly visible to the naked eye is not of Halakhic concern (Iggerot Moshe, YD4:2). R. Nachum Rabinovitz makes a similar argument that even if the insect is visible but does not appear to be a living creature to the naked eye is of no Halakhic concern (Shu"t Siach Nachum 45)
4) The video appears to have been filmed through a zoom lens that paints a picture more magnified than can the naked eye.
What does this have to do with stagnation of Halakha?
A friend reported to me that a prominent Rabbi this past Shabbat delivered a shiur on strawberries. In reviewing the issue, he stated that R. Rabinovitz's book has many radical responsa.
Now ... I've been through that book, and I can find nothing even approaching radical. Original and creative, but not radical. It's not like R. Professor Daniel Sperber permitting women to have aliyot, or R. Sherlo raising the issue of allowing older single women to become pregnant through artificial insemination. Au contraire, his book is filled with good old fashioned creativity and original thinking.
I asked my friend if anyone asked said prominent Rabbi what about the book is radical. Answer: no.
So ... why has Halakha stagnated? Because anyone daring to be creative and ... heaven forefend ... original ... is labeled by his contemporaries as "radical" and the masses nod their heads and accept it.
I find this especially ironic in that R. Rabinovitz is a product of the chareidishe velt.