As someone who works in the field of laminar-turbulent transition (albeit in boundary layers, not confined flows like the Poiseuille and Couette flows contained here), I've not heard of any of this and it was from two years ago. In other words, it must not have been broadly impactful enough to make its way into use in any engineering sense, nor has it found its way into use (or even mention) in the broader fluid dynamics community. That said, I haven't read through all of this yet (and I've downloaded the papers, so I do intend to do so).
From what I can tell, none of this is claiming that transition and turbulence have been "solved". Rather, it seems to indicate that the transition process itself (i.e. the growth and propagation of turbulent spots) can be described using this directed percolation idea from statistical mechanics (a topic with which I am admittedly not very familiar). It doesn't seem to do much to address how the flow arrives at the point where the spots form, nor the actual process by which a flow otherwise dominated by stable and unstable waves transitions to one dominated by the energy cascade that is the hallmark of turbulence.
In other words, this seems to be a potentially interesting piece of a puzzle, but it certainly doesn't form the whole picture.