He is a Zeke Fan-Boy and he over-shadows a few good points with some blatantly false information.
The scheme is the top issue. When watching ALL snaps the individual OLinemen are playing reasonably well in the run game.
The 2nd issue is that Zeke does not threaten defenses to the far outside edge like he did in the past.
Defenses don't quickly jump play-side on outside zone runs which allows them to stay in place against the cut-back or the outside run just outside the OT.
Columbo played in Houck's man blocking scheme. When Bill Callahan replaced Houck in 2012, it was the biggest upgrade in coaching that the Cowboys have had since Parcells replaced Campo. Connor Williams would be perfect with Callahan as the OL coach.
The best way to understand the Cowboys blocking problems is to study the problems the Cowboys defense is having against Zone Blocking teams. ZBS teams are able to box out some defenders just by scheme because they manage to impede some defenders with "traffic" which means if an OL is blocking a defender and those players get in the path of a defender trying to move laterally.
The Cowboys have been trying far to many reach blocks which increase the difficultly for an OLineman to execute. If reach blocks work, then then another OL gets a good angle on a LB but when reach blocks fail it does not matter if LBs get blocked.
Starting with the Eagles game the Cowboys changed blocking assignments in an attempt to solve the reach block problem.
Unfortunately their work-around has backfired.
In the play below they would have blocked it differently before the change and in this scenario their method before the change would have been correct.
They have Martin block the DT and Frederick attempt to kick out to block a LB.
Previously, they would have had Frederick block that DT which would be a type of reach block; however, it is the type of reach block that they should use. There is another type of reach block that was the problem
Envision if Frederick basically does not move laterally. The DT that Martin blocked would take himself to the outside of Frederick initially because the blocking initially appears to be a run in to the side of the LT. Notice the LB takes a step to the outside initially. The DT would do the same on this type of play. If the DT takes a step or two towards the outside, then Frederick would have a leverage block when the run goes inside of Frederick and the DT. Martin would easily be able to block the LB that Frederick could not block in the actual play that they ran.
Just that simple set of blocking assignments for 2 OL is the type of issues that are causing the Cowboy blocking problems.
The problem that they were having with reach blocks is when the DL was flowing away from the OLineman that was attempting the reach block which would force that OL to try to "out run" the DL laterally in order to get to the other side of that DL. On the play in this video the DL would do the work for them and Frederick would only have to let the DL cross his face.
This concept is even more evident on outside zone runs where DL move very quickly to the play-side and can be boxed out when the RB cuts back inside (i.e. What the Rams did to the Cowboys defense over and over).