You are not going to get higher DR until more camera manufacturers use 16 bit and above A/D converters.
You cannot really get more than 14 stops DR from a 14 bit system or 16 stops DR from a 16 bit system. You can make the figures look good by shooting a back illuminated Stouffer step wedge with a 14 bit limited system and you may even come up with 14.5+ DR but that is not a real measure of what one can expect in the field. So while the figures may be useful it can only be useful in comparison to other systems measured in exactly the same way. I do not recall exactly but seem to remember the 645z not getting a full review published with one comparison site when its score was pretty high at over 100 - some conspiracy theorists went on to say....
In the real world you are going to loose a few stops due to noise and it could also be argued that your tolerance of noise may affect the real figures as you may be more or less accepting of the phenomena.
I much prefer the results from Bill Claff's site as they do echo closely what I have experienced in the field.
There are a few camera systems that capture 16 bit including some Phase 1 and some Hasselblads. According to Photons to Photos the Phase One IQ4 (16 bit) 150MP has a Photographic DR of 13.11 (the manufacturer quotes 15 from the 16 bit max). My Pentax 645Z maximum Photo DR = 11.77 (close enough to my own testing at a max of 12 stops) and the Pentax K-1 II max Photo DR =11.60.
There are many reasons that one may buy into a system and DR may be just only one and it may not have such a heavy weighting on your choice over other features and percieved benefits. When Nikon came up with a 2 DR stop advantage over Canon I do not think there was a mass professional migration from Canon to Nikon similarly when Olympus Pentax et al came up with Pixel Shift. The same must hold true with MP count I do not think I would change my 51MP system for a 75-100 MP system as apart from the cost I do not see any technical benefit.
Should Pentax jump from a small to a FF MF sensor of say quadruple pixel count i.e. 200 MP at the price of the current 645z I would certainly sit up and think