Scaling with character level represents the character getting broadly better at adventuring, particularly the class's abilities.
Enemies being statted as minions represent them being far below the party in general combat ability, and, for whatever reason, fighting all-out against them for a shot at slowing them down or harming them in whatever way they can, consequently leaving themselves open to killing blows, having very fragile morale, or whatever, such that they're easily knocked out of the fight. The exact same enemies, facing a much lower-level parties could be fighting them on equal footing, and represented by standard blocks, or against an even less experienced party, could toy with them, pulling off otherwise low-percentage tricks that'd never work against an equal, as represented by a Solo or Elite stat block.
None of that is actually unrealistic, counter to genre, or bad at representing the world. It's just designed around the actual focus of the game: the PCs.
A detailed simulation of all the factors that make a monster that gave you a terrifying battle by itself when you were just starting out, but now you mow through hordes of them, would be downright prohibitive. D&D has consistently failed in giving one set of stats that actually deliver a powerful 1-vs-party threat at low level, and a credible threat at mid level, and then a trivially dispatched but not trivial, threat at high level. It's not impossible, it'd just require a lot of detail, different-level combat maneuvers, rules for toying with lesser enemies, or making desperate attack against greater ones, overwhelming situational modifiers, etc, etc....
As above, that might work, in a far more detailed and nuanced simulation. One not, for instance, limited to the flat distribution curve of the d20.
Aside from 'fictional reality' being a bit of an oxymoron, fictional settings aren't that consistent - particularly, not that kind of consistent. All orcs using the same stat blocks isn't consistency, it's a simplification for playability. A representation of 'the world' where the orcs aren't existentially mooks and the PCs not Heroes, would have each orc unique and modeled in the same level of detail as a PC. When the PCs encounter a particularly bad-ass orc leader at first level and he nearly takes them down single-handed, then, later, having undergone rapid leveling, the PCs take him on again, he wouldn't, if the game were faithfully modeling some imaginary objective reality, have the same stats, maybe the orc wouldn't have had as much experience as the PCs in the meantime, but time as passed and he may have gained a level or switched to different gear or picked up a new trick or even have something he's been working on in hopes of a rematch...
Ultimately, a TTRPG is a game, not a simulation. And whether the DM wants to focus on challenging the players, craft a story that the players hve staring (or secondary) roles in, or present a world for the players to explore, it all happens through the PCs, making them the focal point, if not the focus. Even if the PCs aren't the whole point, they're the point of view.