And it's also a silly example, you had to push a situation to an extreme (a party with 5 familiars) that never happens in the game just to try to make a point. So no, there is no such "context".
Except I didn't introduce this into the discussion.
@GMforPowergamers did. I agreed that they could do it, but that there would be risks and trade-offs and what those might be specifically. If you've got a problem with the example, take it up with them.
I will answer this when you first answer the question that I asked, which is why you are obviously going out of your way to prevent characters from having familiars with even a small chance to live, with sentences like "kill on sight" and "at risk for even having them out, doing nothing".
You're asking a question that isn't relevant, so I can't answer it. As shown in my other posts, the players aren't prevented from having familiars, nor do they have a "small chance to live." I have two PCs in my regular group with familiars, as I stated. So why do you see meaningful choices as "piling on difficulties?"
Then it just proves that you actually don't play your game by your words, as I suspected all along. There is no actual "kill on sight". You probably would kill familiars if the players were doing really stupid things with them, as most DMs probably do, but again it's very different from a "kill on sight".
I do it if given the opportunity. My players know this. They plan accordingly or, at least, understand when they don't why their familiar got taken out. The most recent example of this was when the party was fighting another adventuring group which my random generator for adventuring party names came up with "Four Warriors & A Pixie." So I established that the group had a pixie strung out on fermented honey in their service. They released the pixie from a jar and she buzzed about the battlefield, hindering the PCs during the battle. Among that was using her
dispel magic on the wizard's familiar after he had cast
dragon's breath on it. I thought that was a pretty neat turn and so did the players. (You don't see that every day.)
And again, mules don't necessarily need to be protected unless adversaries target them specifically, and hirelings and henchmen are supposed to be competent enough to survive generally. As you say, it's a dangerous world, so why would the adventurers be the only tough ones ? They might be somewhat tougher, but do they really have to cocoon all other party members all the time ?
If true (see above), that amount of pressure and danger probably incites the players not to use henchmen and hirelings (or mules), which I find a bit of a shame since it in general makes for a poorer game with fewer possibilities.
Overall, once more, it's a question of balance, I'm not saying that they are not in danger in our campaigns (they are, just as the heroes are), but there is no "kill on sight", and no need to protect them and make meaningful choices about them every single minute. Most of the time, it's companionship and having a varied party and having fun without fearing that the DM will pounce on their resources (you claim you do, but I am pretty sure it's not really the case, actually

).
Putting pressure on the PCs' resources, which is part of the game, doesn't
disincentivize taking mounts, pack animals, familiars, or hirelings. It
incentivizes making good decisions when deploying them. The
incentive to use mounts, pack animals, familiars, and hirelings comes from what they can do for the party in the context of the game and however much fun the players derive from that.
If you were correct in your assertions - and you're not - then we might reasonably see no mounts, pack animals, familiars, or hirelings in my regular game. But we do have those things. The PCs have a goat, three mules, 7 hirelings to man their river boat, and two familiars. At the moment, they also have an NPC cleric they just rescued and are traveling a long distance to bring back to town. So they need to protect that NPC too. I'll even add that protecting the boat is also a concern for the PCs - they ran into a monster with the Siege Monster trait recently and almost lost it!
So no, there is plenty of fun to be had here. Maybe you don't like it because of past traumatic experiences, but as I said far upthread, please don't project your issues onto me or my group.