I would agree, if we were talking about a Defiance Deviant that gums up if you put a .001" thick layer of Cerakote on it (yeah yeah, I know... they offer them now optionally with more clearance than they did before). The M5 has something like .010-.015" of clearance on the bolt body diameter, with a tapered rear end that locks up tight as the bolt closes.
It's toleranced to work. Some parts are tighter than others, but there's room for dirt and dust and snow and it doesn't lock up, and the toroidal lugs allow for complete lug engagement even if there is some misalignment (There's not room for much, in any action... Some folks seem to believe you can really wiggle a bolt around in an action...). Precision is the result of a quality barrel, quality ammo, uniform lug engagement, and stock/action interface. How you get there doesn't matter; if you dress up a Mosin Nagant 91/30 the way you would a M700, you will get the same group size. Anyway, like I mentioned before, right after I got my M5 I ran it completely dry in local PRS matches, and Chad Dixon from LRI ran his doused in oil (dirt magnet). We made a point not to clean them or wipe them down and never had an issue. We ran 500 rounds as fast as we could with a fire-forming barrel that got so hot we had to water cool it. We filled the shop with dust and sand from the test-fire barrel there in the shop, it was hot, dusty, dirty, sandy with long head-space cartridges (false shoulder for fire forming). If an action was ever going to gall, that's where it would have happened. The M5 came out spotless, different surface finish where the lugs swept past in their recesses.
4340 with a proper heat treat is one of the strongest, toughest high-strength steels out there. The M5 is not just another M700 clone made to "tighter tolerances", the design work and how these are made is on another level.
ETA: I have no experience with Sakos, but I have shot a few AI's, and IMO the M5 is on a similar level. It's hard to do a direct comparison because one is a factory standard rifle, the other is just an action and is really dependent on the smith doing the work. But I was in the infantry, and I'd have no qualms being issued an M40 built on an M5. I believe it's at least on that level, and I think if the American Rifle Co. grows, I can see them producing complete packages similar to what AI puts out.