And the "mark" corresponds to nothing in real or simulated life, it's just a way for the tactical boardgame to replicate the aggro mechanism of MMORPG, otherwise (barring roleplay) the role of tank does not really exist (which is more or less the case in 5e except using enchantment magic such as compel duel.
And the basic fighter's mark has nothing to do with sentinel.
It...actually does correspond to something in real life. Because the whole roles thing was heavily inspired by
football (soccer for us folks north of Mexico).
It's literally the reason why two of the roles are called "Defender" and "Striker." Defenders
mark opponent strikers in order to deny them the ability to control the ball. That's literally the term used, and very good IRL defenders can throw opponent strikers entirely off their game, while very good strikers know how to evade or break an opponent defender's mark so they can easily score.
And this is, again, a demonstration of what I meant by saying people make sweeping generalizations without knowing the game or its context. 4e
constantly got people saying either mistaken or outright false things about it during its life, and I am not going to stop pushing against those things now. Marking repeatedly gets compared to "threat" or "aggro" from MMOs, just as you said, but it is
literally exactly the opposite of that. A "threat table" FORCES creatures to always attack whoever is at the top of the table, they have no choices, no thought, just brute calculation. Marking is literally the opposite of that: it creates both a cost (creature will take damage if it ignores the person who marked it) and a risk (-2 to hit if an attack doesn't include the person who marked it), meaning that the person playing the marked creature must
choose whether to eat the cost and take the risk, or play it "safe" but attack the hard-to-hit defender. By forcing
choices rather than inflicting raw-numbers
mind control, the mark actually quite accurately reflects the ways that real defensive fighters--those protecting more-fragile but more-potent allies--manipulate the battlefield and their opponents in order to secure victory, whether on the soccer field or the battlefield.
More importantly, the cost was always diegetically associated with the nature of the class that provided it. For example, the Fighter's marking mechanic, Combat Superiority, is specifically tied to making attacks, and its punishment mechanic is getting to make an extra attack against that target. It does absolutely nothing (other than the -2 to hit, representing the marked target's wariness
due to having just been hit) unless the Fighter remains within range to attack the target. This means Fighters want to get up close and personal with their enemies, or use reach weapons so they can lock down more foes. As a contrasting example, the Paladin had two marking mechanics, Divine Challenge and Divine Sanction; Divine Challenge required that you stay "engaged" with the target in order to maintain it (doing damage, physically approaching, etc.) while Divine Sanction was always some kind of set duration, often one round but sometimes not.
You didn't have Fighters magically mind-controlling enemies. They had to physically attack a foe in order to mark it, and the mark would only last until the end of the Fighter's next turn.
I also rather heavily dispute your accusation that Rituals were siloed off into a totally separate part of the game. Ritual components were expected to be rewarded frequently in treasure; several classes (Bard, Cleric, Wizard, Druid, Artificer, Invoker, and Psion) get the Ritual Casting feat for free. The rituals list was continuously expanded throughout 4e's lifetime, and parallel options (Alchemist and Martial Practices) were added for folks who wanted a different means of gaining non-combat utility stuff beyond what was offered via Utility Powers. They also added Skill Utilities later on, many of which are not at all useful for combat applications.
4e made combat a rich experience. It
did not do so by impoverishing the non-combat experience. It simply made the two things use distinct resources.
Edit:
You're also straight-up
wrong about the 5e Sentinel feat. It functions
almost exactly the same as the Fighter's mark punishment: "When a creature within 5 feet of you makes an attack against a target other than you (and that target doesn't have this feat), you can use your reaction to make a melee weapon attack against the attacking creature." (The 5-feet limit and the "target doesn't have this feet" requirement were added by 5e, but otherwise this LITERALLY IS how 4e Fighters punish opponents that disobey the mark: making an attack against the attacking creature.)