Maybe the advances are not as big today, but i suspect they are still working on it.
Indeed so, -in 2007 I started work for a company who were enthralled that the Cambridge University Gallium Nitride dept in UK had stated in all the main newspapers that in three years time they would have LEDs available for the mass market which would be at least 300% more efficient then the LEDs currently existent at that time (2008).
This obviously never happened.
It seems to me that LEDs have hit the end-stop.
The only thing we get increased now for LEDs is marketing spin.
Even wiki contradicts itself over CFL vs LED......look under CFL then LED and you find contradictory statements.
What I do know for sure is....
LEDs have unfortunate directional properties, need big heatsinks, and are more expensive than flu.
I am told that its easier to build a 10 Watt offline led light bulb without using electrolytic capacitors than it is for CFL....but im looking into this.
Also, in USA, mains is only 110VAC.....I sometimes wonder if when rectified into a smoothing capacitor, -is that enough voltage to properly and efficiently drive a CFL?.....I don't think so....I reckon in USA, maybe LEDs are therefore better than CFL....especially if not much smoothing capacitance is used and the DC (post rectifier bus) dips significantly below 100V say.