Players closing off the possibility of plots revolving around NPCs and institutions that they care about are really cutting out a lot of possibilities for engaging adventures.
And what I find so strange is the idea that the adventurers don't care enough about npcs and institutions they encounter in the course of actual play for those to be a source of conflict and consequences.
In what kind of game do the adventurers earn no friendship or gratitude, make no rivals or enemies, meet nothing and no one of importance?
It's also really hard for DMs to keep creating plots about brand new NPCs and situations that the players will endlessly care about:
"Oh, another princess needs rescuing? OK, I guess."
What happened to the consequences from the rescue of the first princess?
Princess Pinkflower is delivered from the villainous grasp of the lecherous baron de Bauchery; her family is grateful, the adventurers are feted and rewarded.
But what of the baron, or his heir, if the adventurers finished him off? What about the secret society of which the baron was a member? What about the suitor to the princess who's been shown up as ineffectual at best, a coward at worst, by the adventurers? And his family, which has the king's ear? And what of the princess' younger sister, who is now looking at a 'politically advantageous' marriage again, which means betrothel to some marcher lord with the manners of a pig?
If the adventurers win, somebody else loses. Figure out who loses when the adventurers win, and you don't need to write plots or make up stuff from their backgrounds anymore, because the game becomes a perpetual motion machine.
. . . [T]he whole party should be happy to help rescue the cleric's family farm or help the paladin do well at the jousting tourney and impress his beloved.
Now this I agree with.
The relatives and friends and sweethearts should also be patrons for adventures, sources of information and other resources.
And this, too.