I do agree that in terms of bang-for-the-buck, JBL's "popular" ranges are a hard-to-be-beaten choice.
I take as an example my Northridge E Series; they're far to be considered JBL's best effort and still they sound that good.
Very recently I've got a very modest outboard amp. for the L / R mains (my first one) and I've never heard those babies sounding that good, with lots of dymamics as I never heard before...
Listening tastes varies a lot and in my specific case (pretty reflective room), the JBL's fits as a hand in the glove, because their nature is to provide a warm sound, though.
With that being said, I'd like to say that those big companies must have their "big box ranges" , in order to keep business going on; otherwise profitability drops very quickly in to the red lines...
Let's get the 3 biggest known US brands, as an example:
JBL
KLIPSCH
POLK
They all have their Ferraris & Civics as well. Why? they're all giants and need to sell, simple as that (they wound't be what they're now only selling Ferraris, right?).
Let's not forget about the name they bear also. I'm sure that wherever you're on planet earth, if you talk about speakers, someboby will mention JBL, Klipsh or Polk in a glance. There's a lot of tradition, reliability, R&D, etc., involved on their achievements.
JBL is celebrating 60 years now. How many speaker manufacturers are that old?? As a rough reference, one can compare them to brands like Coke, Pepsi and Marboro, for sure.
Bottom line is that I'm not - by any circumstances - saying that they're the best bets in the market, but they do fit the bill in most cases, in a very confortable & affordable way. ID brands are, for sure, another excellent option, so they can produce high quality products with a much lower cost.
I'd even dare to say that I'd be equally happy if I had to go Klipsh, Polk, Ascend, SVS, HSU, AV123, Axiom, Infinity, etc., etc., etc, but I've been a JBL guy since the 70's... I might change my mind someday, who knows?
Cheers.