Looks like that's what happened. Obviously I don't have numbers so this is the purest-cut speculation, but who knows what would have happened if everyone started playing Online Franchise from the start? Maybe EA were expecting greater numbers to take it up after a lot of grousing and quickly discovered not enough people were playing the barebones version. Then as a company do you devote constant resources to update something slavishly for a small fanbase, or concentrate on trying to bring new customers in for M11 when sales aren't being boosted by introducing more "hardcore" features?
Remember also this was the first "online pass" feature ever, IIRC (if not, ignore me) Those numbers using it weren't going to be boosted much by the used market who could go onto play now instead. You also had a lot of problems with International customers in M10 where the codes weren't in the boxes and it was down to ringing a hotline to rectify the situation. I know that's a tiny fraction of sales, but every one counts.