I dug through some of my old books yesterday, finding my much abused and long-possessed copy of Keep on the Borderlands. Reading the opening paragraphs of the introduction, I found the following passage under "Notes for the Dungeon Master." I presume my readers will be interested:
"The DM should be careful to give the player characters a reasonable chance to survive. If your players tend to be rash and unthinking, it might be better to allow them to have a few men-at-arms accompany them even if the party is large, and they don't attempt to hire such mercenaries. Hopefully, they will quickly learn that the monsters here will work together and attack intelligently, if able. If this lesson is not learned, all that can be done is to allow the chips to fall where they may. Dead characters cannot be brought to life here!"
Of course they can be according to the AD&D Player's Handbook, but my first run copy of the module does make it clear that the scenario was designed for the Dungeons & Dragons Basic Set.
I don't actually have any issues with the argument that we should give the players a reasonable chance, though this varies widely from DM to DM. Men-at-arms is a good idea, but rather than "give them" I would rather suggest to the party when in town that they might consider it. Then it is a choice, not the DM deciding that these men-at-arms are going to go along, period. Nor do I have any problem with the reality that the party may die if they can't learn to work together, as we absolutely expect the monsters will. So this isn't going to be a rant against Gygax - more's the pity.
What's interesting is the historical perspective here. We've all followed the so-called Old School Renaissance and that 5e hearkens back to the original game - but in fact many of the sentiments that were inherent in the game have died away. For many systems, it is so hard to kill the characters that the DM hardly need be concerned with giving reasonable chances. The balance is nearly always in the characters favour. It is also far more likely that the DM would give out magic items rather than followers, as these are more reliable and effective. And certainly the idea of punishing players for bad play has become passe.
The reference here to "rash and unthinking" players relates to players who rush forward into traps or combat, getting themselves into trouble and thus getting killed. Today, however, "rash and unthinking" is more likely to be applied to characters acting out in a childish manner, killing important characters in the DM's campaign for shits and giggles, lighting towns on fire for fun or otherwise acting like morons. I rarely see anything about characters who take too many chances in combats since the rules have been redesigned to ensure that if a player rushes his character stupidly into battle, there are plenty of hit points and healing to be had, ensuring the character won't die. There's no need to warn about that because - except in rare cases - the problem has gone away.
For me, the most interesting part is the assumption that the monsters will act rationally. Each time in the past few years that I've been able to witness a combat - or see something presented online - the monsters rush in just like the players, so that everyone stands toe-to-toe until attrition finally wins the day (usually, whichever side has the most healing). Strategy? Never heard of it. By transforming magic into a series of blows that work like ranged fighter attacks, all the characters are so similar in combat that there simply isn't enough variation in the participants to make tactical design worthwhile.
This heterogeneity in attack forms is the deepest problem in the present game, as near as I can tell. Without weakened, nearly dead characters to protect, with missile combat being almost exactly as effective as hand-to-hand, with spells working like fighter blows round after round, the melee found in most games more closely resembles the sort of trench warfare found in World War one than it does the wild free-for-all of former adventurers fighting. The result seems a degenerative banality.
From what I understand, it would be horribly impractical to add more men-at-arms to the party anyway. Combat takes so long to resolve that the addition of five or six more figures would grind the momentum into cement sand. Perhaps this is a reason more magic became standard.
I think we've definitely lost something. Those old words by Gygax are quaint by today's standards but they reflect a change in attitude that has greatly reduced the threat the game once imposed.
I would suggest for many DMs that they should take steps to greatly minimize the amount of healing available to players, along with cutting down the damage done by missiles and magic, on the argument that characters who aren't risking getting hit shouldn't be able to carry the weight of the combat. These changes will greatly press the forward troops, making combat more fearful, while reducing the power of those backing up the play. I would suggest that even if this doesn't seem fruitful, that a test of some kind should be tried. Seeing the players react to the changes (even if they know they aren't permanent) may tell you a great deal about why your game seems so grey.