There is a bit of slamming supposition there.
I know you don't like Snead, but it's personal because we have NO IDEA, as in zero knowledge, about how he has done his job. So to say that McVay is more on the ball is a guess and no more that that. As the new HC it is his job to reach out to HC's, part of the reason guys get hired is their connections so this is nothing unusual. The stance you seem to be taking is that only McVay has done that.........and that's not true because it happens this way pretty much all the time.
As far as him not being able to trust Snead to evaluate talent that's purely speculation, and most likely incorrect at that. Snead is still on the staff.
Why would that be? My guess is that his bosses think he has done a good job. We have NO IDEA what has transpired in the hallways and meeting rooms etc all we know is what we have seen happen "publicly". Snead has added talent, or at the very least laid out options for Fisher to choose from since Fisher not Snead had final say. He also has done an excellent job targeting trades and executing them. He's also done a stellar job finding street free agents after the draft that are solid to excellent contributors. Right now we aren't 100% certain what the flow chart looks like and who will be doing what and all that, so lets see how it unfolds.
McVay does have his work cut out for him. He's taking over a team that needs to learn a new offense and a new defense. That's a big job by itself. Now add in that he is tasked with developing a QB from scratch and teaching him a new scheme. He also has to finish rounding out a staff. He has to rebuild the "feeling" in the locker room too. It's going to be quite a bit of work for him. Hopefully he gets it done.
Right now the two most important people on the payroll are Goff and Snead. If they don't do strong work nothing else will matter.