In our modern world we have frequent recourse to interact with large institutions. Whether you're employed by one or merely have business with one, you've seen the kinds of deep-seated root-level stupidity that plagues them. And this isn't because the institutions are stocked with morons. Far from it, it usually appears that one or two uniquely incapable people reach a bottleneck and clog the arteries of communication, killing all the workers down the line by starving them of necessary information, assistance, or whatever is needed. This institutional stupidity is something that inheres only in strongly redundant organizations. What do I mean by this?
Where institutional power is weak and things are accomplished more by individuals taking initiative than by following the proper channels, individual people have a tendency to communicate more. Failure falls not on the fact that a message slipped through, but on the fact that someone fucked up if a message wasn't delivered. In a well-organized and redundant institution, this missing information is likely not to be fatal to the organization as a whole. This is why it has safety valves, catches, and redundancies. In a smaller or less well organized institutional structure, these safety valves don't exist and failure won't be caught by the net installed to make sure their big kindred can continue lumbering on. Indeed, it is the very inertia of powerful institutions that makes them immune to small-time scandals of this nature.
Why am I even talking about this on a blog about D&D? Because there was far less of what I would qualify as institutional stupidity in the ancient world and the middle ages. Institutional power simply wasn't entrenched well enough to allow petty bureaucrats to gum up the works with no negative results. When the gears began to stick, people noticed, because it could lead to the loss of lives and livelihoods. This is something of an overgeneralization, which I am loathe to make*, but generally institutions were extremely weak if extant at all.
Institutions as we know them require structure, legal backbone, organization, and precedent. Crisis in the pre- and post-Carolignian world (the Carolignian Renaissance, as it is called, saw the emergence of temporary but not particularly robust institutions for administering the will of Charles) was generally dealt with in terms of individual situations. Each problem was a problem for an individual solution. Of course, again, there are cases where this isn't true—the ealdormen and shire reeves of England, the vast canonical courts of Rome, etc. However, the scale of institutions was greatly curtailed, the types of problems they dealt with were extremely specific, and they were generally much more vital (accepting of and capable of reacting to change) than modern institutions are.
The upshot of this is that your PCs are less likely to be "forgotten" by an institution and let slip through the cracks. They are unlikely to weasel their way through loopholes and use the inertia of bureaucracy to escape the eye of those in power. On the other hand, they are more likely to obtain power themselves and be permitted to exercise it. The lack of institutional safeguards cuts both ways.
*And here's where I take it back piece by piece. The Romans, of course, had much stronger institutions, which were necessary for the governance of the empire. Even after the Western collapse, in the east the Romans continued to operate on a much more organized and, indeed, institutional level.