I make a reasonably detailed, but short backstory for a character if I'm making up a character that already has experience. Say, for creating a 9th level D&D character. If I'm making up a new, 1st level character then it's a couple of sentences, at best. What life experience does that character have? Pretty much just getting to 1st level. I don't understand how people can claim their 1st level character has done a ton of heroic things, before their essential 'birth' as a PC.
And I think that I've used the usual tropes maybe twice. Once was for a 4e Feylock who was orphaned when his (minor Feywild noble) parents were murdered and he was thrown out into the Prime, to die. That was as a nod to why he made a Pact and why he hated one of the main antagonists in the campaign. The other was for a Pathfinder Evil campaign. He was a street urchin who had a somewhat high CHA and was recruited, trained, and finally sent to a rival nation as an insurgent. Ended up as a FTR/Ninja, at later levels. the orphan thing was just an expedient to explain why he was where he was.