I fully get what you are saying...the allocation draft can be a grind as is starting a new league. Trust me, I've started enough of them and filling 31 teams takes effort and active recruiting over the course of 2 weeks or more.
I'm not against an option for new leagues to auto draft teams...it's just not something I would be personally interested in because the A.I. is making 46 roster decisions for me which will establish my francise for the next 5-10 seasons.
There are plenty of established leagues where you can take over a francise and mold them to your liking. I have 2 leagues in or near season 25 and I still get 1 or 2 openings every year.
Just like roster management leagues, auto drafted new custom leagues can be an option. I'm not against options but I don't see a fit personally for me.
As league admin for 3 full leagues, I get the frustration of starting anew and finding 31 owners. It's work and offering added content which differentiates your league from others also gains you owners.
Custom power rankings, MVPs, ALLPROs and a Hall of Fame are a few things I offer in my leagues along with team and owner Alltime records, draft grades along with draft reviews.
It really is a supply and demand model with demand limited to roughly 300 owners and a supply of around 50 different leagues.
In the end, the most successful leagues are run by active league admins who add content and create a more immersive experience for any owner.