I disagree. Only Bioware would have the actual data, but I expect most casual F2P players are only going to buy the bare minimum from the CM - character slots, quick bars, artifact gear and escrow unlocks, etc. Maybe an occasional unlock for an operation. But I'd be shocked if F2P accounts spend more than $10/mo on the game on average.
When I say casual players I do not mean f2p but I believe there is a significant portion of subs who are casual players, not doing end game content (ops or hm fps) leveling alts and mostly playing the game as a single player game. you guys I think underestimate the barrier of entering into an ops group even with a guild support. I know a lot of people in my guild don't do any ops or hard mode fps.