I, too, have noticed the deteriorating service levels on my B6 flights lately.
It hasn't been a precipitous, all-at-once drop, but, rather, a slow slide which has become quite noticeable lately. The flight attendants on my last flight were, in a word, disinterested in anything other than standing around gossiping and complaining.

Combined with their poor on-time performance record, JetBlue's slipping service is really showing me that, finally, the "bloom is off the rose" at JetBlue.

And, I have also noticed that their fares aren't any cheaper than the other airlines anymore.

Guess it was bound to happen.