The latest TOTL JBLs use (bi) radial horns, and the fairly recent K2 S9800 used a radial horn (H9800) very similar in shape to the 511 and 811: H9800
The H9800 is a BiRadial; it is a constant-directivity design based on the work of D.B. Keele.

More recent horns sometimes offer better dispersion it's true, although IMHO the verdict is still out as to whether a CD horn offers better sound for hi-fi listening, as opposed to pro audio, where you need the dispersion. Dispersion is a two-edged sword; the sound radiated over a wider angle will cause more room reflections and hurt clarity.
Room reflections will not affect clarity so long as RT60 (reverberation time) is sensible and room modes are well-distributed, and additionally an even power response yields a spectrally balanced reverberant field.

This was the impetus for developing constant-directivity design and it is nearly impossible to find contemporary control room monitors or even well-designed high-end audiophile loudspeaker systems that do not have even power response.

A lot of audiophiles seem to prefer the LeCleach and Tractrix horns, both of which have collapsing directivity with frequency. A design like the 511 or 811 strikes a compromise for dispersion, one which I'm happy with.
Good directivity index is only one criteria inherent in horn/system design (albeit a very important one); others include good low-frequency loading, low second harmonic distortion and freedom from unwanted constructive/destructive interference and diffraction. Commercial designs attempt to balance these depending on intended use (cinema, sound reinforcement, critical listening, etc.)

Apparently those audiophiles are willing to sacrifice certain attributes to maximise others.

BobR