"Exactly. Most of the time No" - I think you just contradicted your intended argument.
Most of the time, no, means yes you can have two profiles live at the same time. So they should be able to do it. In fact, your statement suggests that they are able to do it.
Not sure why anyone would argue against changing a game in a way that makes it better, for more people. I've heard no convincing argument yet.

Sorry if my comment was unclear, but it's suggesting that "most of the time, No" means in most online cloud based games, you can't use multiple active profiles simultaneously.
I actually don't believe having two active profiles would make this game better. Here's why:
-Consider games allowing multiple profiles to play simultaneously in a season online and or local season not online. None offer course customization in a cloud space shared on three platforms.
(Locally there are games like Madden, or FIFA but it comes with other limitations. Typically it's one profile at a time because you need all the other online functions and features.
(So if it were added....possibly)
-You still would have to be online and all profiles would need Xbox live gold and join the same online society and same event from start to finish and not allow you to stop in progress.
-Local career play is limited to one profile not multiples, so this right here is the obvious reason why it doesn't make sense to add it if it's going to be limited.
-save data is game specific + profile specific so we would be asking them to make save data profile specific and have another game specific save data that both have to exist in the cloud and always upload to clear save data error but if someone goes offline and doesn't upload, the other players progress is now out of sync. Do you just delete it or what?
-It would further complicate trying to add real players as there would have to be access to 4 different friends lists simultaneously
-It would put a huge strain on the local console trying to pull and push all that data to their server and Xbox live
-Technically speaking, it wouldn't make sense for someone else to be able to add you to their session live outside of online society gameplay, because you're already playing with a two-some, three-some or four-some.