Having worked in an auto shop, I believe the reason you don't find Alldata or Mitchell for bicycles is it would be a drop in the bucket for the publishers vs what they already get from automotive.
These publishers are really in it for the money, and there are simply just more garages than bike shops.
It takes a ton of r&d and co-op with the manufacturers, at the end, who will actually subscribe to them?
Wrenching labor is also nickels and dimes for bikes. The same work can vary from one shop to another by a great deal, but so what? Whether a same job is $50 or $100 won't make a difference to both client that can afford it or the shop that has too many expenses.
When a client doesn't want to pay a shop for a repair, they are just told to screw off, the shop doesn't need them, doesn't even matter if their rates are above norm.