For DnD, I normally aim for six players, and I run if there's at least four present.
Knowing that the game will go on anyway without you is really good motivation to not flake out (I speak as someone who flakes out a bunch.) - and DnD is a very easy game to just have someone be not present for a week.
Serious question, I don't mean to offend (at least not yet ;) ) - do you only ever play DnD? Because this community is called RPGmemes and I rarely (if ever) see anything but DnD.
It's a shorthand for folks outside or new to the hobby, it skips a hurdle to talk to people about other RPGs with those people, and it weakens the brand identity. Considering how much D&D has coasted on brand identity as the game suffered, I'm all for that.
I'm less likely to do it places like here, because it causes more confusion, but still. It's fun to say, "Pathfinder is a great way to play D&D." :P
I prefer TTRPG because it doesn't give free advertising to Hasbro. Even if most people know what you mean, someone googling D&D ends up at Hasbro's product.
Personally, the game I run the most is Shadowrun. Managed to transition my DnD group to Pathfinder 2e and it's great. Pathfinder is DnD but so much better.
We finished a five year D&D 5e campaign, now we're bouncing between Fiasco, Brindlewood Bay (murder she wrote with Cthulhu), Mothership (Alien or Starship Troopers vibes), and soon a Star Wars EoTE. Most every game is fun!
Swapping my own group to PF2e and we've all played other systems (lancer, sw saga, vtm, cyberpunk, kids on bikes, etc). I do think if a meme says something different than DnD (using it as a generic term for TTRPG) you'll get more people commenting on the system rather than relating to the meme (like if this said Traveler there'd be more comments about never played Traveler or if it said PF2e comments would be more about the system war).
I don't get group who can't play when one player it missing. We all know that life happens. If a player miss, we play without them, if she GM miss, we do a one shot
Yesterday, one of my players just plain forgot that we scheduled a game.
Luckily, the party was split up doing downtime activities anyway, so we decided that they simply could not locate that character quickly (time was somewhat of the essence). Near the end of the session, the party realized that they need that particular character's alchemical expertise, giving them a great reason to actually go look for him.