The problem with TTL is that each manufacturer has developed their own protocol to control the process.
A third party, such as Profoto has to reverse engineer the protocols for each manufacturer's implementation and then install it into the device.
Companies such as Yongnou, Nissin, Phottix and others have accomplished this for multiple manufacturers.
Nissin has a nice solution with the Di700 NAS, and Phottix has a promising solution with Mitros +, Odin, and Indra.
Profoto is probably too arrogant to license the reverse engineered firmware from anyone so will have to invest the engineering resources to accomplish the reverse engineering themselves.
And, given their customer profile, there will have to be a lot of professional interest to justify the effort.
When Phottix gets the Odin II done and working with Canon, Nikon and Sony, they will be the system to beat.