I don't agree that that constitutes "trivialization" of the encounter. It makes it a regular encounter where good planning and good tactics and good use of terrain result in victory, possibly even a victory at little cost to the PCs. The original claim was that you can't use hobgoblins at high levels because AoE spells trivialize the encounters, and that claim has been thoroughly debunked by subsequent discussion including your recent post
Okay, I'm with you there. I could quibble about whether enough arrows would actually hit for 80 HP+ of damage, but that's not the significant point.
In the sense that you meant - and I am clearer now than before, on the distinction - 100 hobgoblins are non-trivial opposition. As in, something to be played out, one way or another, combat or not. The PCs have ways to establish advantage way before initiative gets rolled, or to prevent an initiative roll from occurring. Back to the topic of spending gold, they might bribe the hobgoblins to let them pass (or to attack some other city, whatever). They might use an illusion to scare away or misdirect the hobgoblins, but that costs a spell slot and thus changes the resource reserves they had before and after they came across the hobgoblins. If breaking the hobgoblins as an armed force is necessary, or even killing/incapacitating many of them, then the PCs still have ways to win, and fairly handy ways to win if they're clever and are "on their game" before direct contact, but those are also things to play out and also might cost resources.
If that's what you meant by nontrivial, then sure, you're right, carry on, sorry I misunderstood.
I was thinking trivial/nontrivial in the sense of "is this an encounter the PCs might lose". If the PCs are clever or just methodical, and willing to expend some resources, then no. The PCs, when they know the terms of the encounter, can reasonably tell NPCs such as a city council, "don't worry, we GOT this, consider it handled". The PCs then still have to actually handle it, but the city council can have reasonable confidence that this particular horde of 100 hobgoblins will never cross the city gate. Again, bar disaster - the outlier odds in which any event (including "I go to the store for milk") could become an unexpected failure - which can happen, but only if something goes very, very wrong.
I was playing in a 5E Adventurer's League game, and at one point, the PCs entered a destination area (abandoned temple) guarded by a force of kobolds and urds. After two rounds, the DM proposed to handwave the rest of the encounter, on the grounds that we clearly had enough power to defeat them handily and to then heal any lost HP easily (one player had a healing feat and a medical kit, another had a reserve of 30 Goodberries, etc.) I voted for playing it out, so that we the players got practice, against an easily-defeated foe, in running our PCs as an effective team... because there were likely to be harder foes deeper within the temple complex, and player experience in easy fights could prepare us for effectively handing not-so-easy fights. So we played it out, eventually the surviving kobolds broke and ran, the ranger picked off a few fleeing foes, we healed a few scratches and then entered the temple complex. It was a reasonable use of session time, not to see *whether* we'd get past the guard force, but to see *how* we'd get past the guard force. I also think the DM's offer to handwave the rest of the fight was fair, and another group of players might have reasonably taken the offer. That's my from-played-experience example.
If a table spent over an hour of session time on the attack and damage rolls required to mow through 100 fanatic-morale hobgoblins, then I might change my mind about what to play out and what to handwave, just sayin'.
Are we now on compatible pages, if not identical pages?
When you assumed that I would use Meteor or Fireball, when other spells are much more effective (and slot-cost-effective) for that encounter, I was kinda wondering if I'd end up ignoring you. I'm now seeing you as someone with significant points, at a deeper structural level than spell tactics. FWIW.
"Quantity has a quality of its own." - Is that from Stalin? Well, yes. There's ways to use 100 troops and still have most of them afterwards, and there's more ways to use them if you don't mind having only 20 or 50 of them afterwards.