The lack of Lathe CAM options is down to the limited number of CNC lathe owners, and I'd guess the larger majority of those are professional users where paying for good CAM is not a major issue.
There are far more mills and routers than there are lathes, and lathe CAM is alot more complex than standard mill CAM.

One thing that sticks in my mind is Art Fenerty mentioning that writing LazyTurn was essentially a lesson in collision detection. External turning you have to deal with avoiding all the tool edges colliding on the profile, and internal turning you have to deal with the non cutting edge having enough clearance in the bore.

Have you had a read through the main thread about LazyTurn on the Mach forum?
I'm pretty sure that's where Art mentioned alot of the issues he had to work with, and I'm sure it would provide you with a good insight into what's actually needed to get a good lathe CAM.