This observation is inspired by the DCC thread, which got me thinking about my introduction to RPGs, which was when I got the magenta Moldvay/Cook boxed set for Christmas in 1981.  My brother, my best friend, and I quickly created characters and started playing "Keep on the Borderlands" and then just kept picking up modules that fit our character levels.  We were running on average 3 PCs each with 2 players and the other person serving as the DM.  But initially it was basically a glorified board game of killing enemies, taking their stuff and leveling up.  We had no extensive character back stories and our characters' traits and personalities grew out of the in-game situations but there wasn't any serious attempt to roleplay.  By the time they reached high levels, they were pretty distinct, however and everyone had a character arc of sorts to point back to.

This, to me, is something that DCC and retroclones like OSE seek to emulate.  Yet ironically, games like L5R and The One Ring from Free League seem to aspire to the opposite, claiming they encourage roleplaying and character development but doing so via tons of intrusive dice-rolling mechanics to tell you how your character "feels" or whatever.  Personally, I greatly prefer the older method.

Just an observation.

Questing Beast talked about this:
https://youtu.be/j-ywPjMEtq4?si=dRpFpaGGbA32GLL2

I think the basic observation that the longer you play a character, the more developed that character will be would be broadly true of pretty much any RPG. I can't say I see anything about OSR games which is directly targeted at encouraging that. I suppose you could argue that since the characters are so undefined at the beginning, they have more room to grow.

I haven't played L5R or TOR, and I generally dislike attempts to mechanize a character's personality, though certain games do at least take an interesting approach to it (Pendragon comes to mind). What I can say from personal experience is that I find the "glorified board game" approach to RPGs quite dull. It's much more interesting to me to play a character with at least a somewhat defined goal, personality and moral code. That can be something you come into the campaign having already conceived of, it can be developed through the events of the campaign, or it can emerge out of the dice rolled during character creation. All three work fine, and personally I suspect that a combination of them is optimal.

Totally agree. The character is not the sum of its stats and rules. Its the story you tell as the character gains levels. Its the "remember when you ..." stuff.

I've always been partial to the idea there are two "backstories" basically, and both are important.

There's the "where you came from" which should be done when you create the character. This doesn't have to be (and SHOULDN'T be) a novel, but a paragraph or two at most saying where your character came from (vaguely if the world isn't fleshed out), what prompted them to become an adventurer, and how they ended up in the starting area for the campaign.

Then there's the "What have you done" which is where the in-game stuff should come about. Your backstory shouldn't include anything major that would be the subject of an adventure (but it might be something like "Orcs attacked my village and I grabbed a sword and helped fight them off"), but could (should IMHO) include potential plot hooks that might bloom into future adventures.

I think mechanical rules for roleplaying create distance from the character and discourage immersion. In Theory-talk they encourage Author Stance not Actor Stance - the terminology is poor since actors don't necessarily immerse, & Forgeists seem incapable of immersion. I think rules for roleplay may actually come out of a sort of "brain damage", to coin a phrase - some people don't immerse in the character they play & thus don't really see that as a goal. Instead they think in terms of story creation & character "arcs", like they were writing a book or directing a film.