Do you have a reference for this claim? In my understanding JFETs are used because they sound good, potentially its also a fashion thing. One thing's for sure, JFETs do not have increased gain (where 'gain' means transconductance) over bipolars, they do have a noise advantage in certain circuits where the impedance is high, though it depends on the particular JFET in question. If a high input impedance is a requirement to an amp then a well-chosen JFET will be quieter than a bipolar.
I never said that JFETs have more transconductance/gain than bipolar transistors. I never even mentioned bipolar transistors. I simply said that JFETs are used in lots of current day tube gear. You asked for examples, look at any ARC product. So let's not confuse the issue by bringing up something I never said (JFETs vs. bipolar transistors). I don't know if ARC is making a single piece of gear (preamps, power amps, and phono stages) that doesn't use JFETs.