……there's an awful lot of "real matter" in the universe…….
Dark matter is real matter. It's just that it doesn't radiate any energy so we can't see it. Neutrinos also do not radiate any energy but they are certainly real.
Maybe all those Dark Matter calculations were… premature.
Doubtful. Dark Matter was first described by Fritz Zwicky in 1933 to explain the differences in the movements and masses of galaxies in the Coma Cluster. To put that in perspective, Edwin Hubble determined that the universe was expanding by observing Cepheid variable stars only 4 years earlier. Neither concepts can be considered premature 85-90 years later.
I'm not sure either Tanimura or de Groot have visual evidence of these baryonic filaments, their observations fit well into complex modelling systems. Therefore these filaments are still considered Dark Matter. It's just that we possibly have a better understanding where this missing mass can be found.
…….after all, the consensus models say something different.
They do? Not according to de Groot, et al.:
"Cosmological simulations predict that the 'missing baryons' are spread throughout filamentary structures in the cosmic web, forming a low density gas with temperatures of 105−107 K. Previous attempts to observe this warm-hot filamentary gas via X-ray emission or absorption in quasar spectra have proven difficult due to its diffuse and low-temperature nature. Here we report a 5.1σ detection of warm-hot baryons in stacked filaments through the thermal Sunyaev-Zel'dovich (SZ) effect, which arises from the distortion in the cosmic microwave background spectrum due to ionised gas."
arxiv.org/abs/1709.10378v1
Paddy is correct. This seems to support the consensus view.
Now does that make this all correct and accurate? No idea. The explanations and calculations that indicate the existence of these filaments and the Monte Carlo null tests that establish the reliability of the evidence is beyond my pay grade too. 
paints grey horses - specifically, dapple greys.
