A lot of RPG's have multiple faction questlines pertaining to different specialisations within the game (the mage questline, the thief questline, the warrior questline) and usually there is nothing stopping you from doing all of them. And that's fine! I get that on multiple levels, both "not wanting to lock the player out of too much content per playthrough" and also like. Odysseus dabbles in all sorts of shit and cavorts with all sorts of people and develops an extremely wide range of skills in his adventures. The kid from The Belgariad (did anyone else read these?) has all sorts of mentors and picks up useful skills from all of them
But the thing is, Odysseus or the Belgariad kid don't become Grandmasters of everything they dabble in. The heroes of old epics/90s YA series may hang out with thieves, and learn about thieving, and become a very good thief, but they rarely surpass the main thief guy at thieving. Meanwhile in videogames you are always the big dick main dude of every single faction sidequest. You put in a few weeks of work and become the grandmaster of every guild. At once. And everyone's cool with that
And the thing is, it doesn't have to be that way! You can let players do all the faction content in one playthrough, and do a better job evoking those stories, and create more investment, all for the low low price of having characters besides the PC matter. Write a little side protagonist for each questline, let them take the spotlight, you learn from them, you help them, but at the end of the day, this is their jam, and you have to move on. Of COURSE you can't stick around and be grandmaster of the companions and the college and the thieves guild and the dark brotherhood, You're busy being the Dragonborn! But the Dragonborn still needs all sorts of teachers, and allies, and contacts, and maybe they can become the grandmasters of whatever it is they're good at.
I don't have a good ending for this little mini-essay but I feel very strongly about this and I wish more games did this right! If anyone actually reads this to the end I'd love any examples in the replies