Ultimate team makes EA $650 million dollars a year.http://www.ign.com/articles/2016/03/02/this-is-how-much-money-ea-makes-on-extra-content
Get your head round these numbers. Think about it. Over half a billion. A year.
Career mode is an absorbing mode which stops folks from playing FUT. Career mode is the enemy of FUT, which is why EA will intentionally keep it rubbish.
Ever wondered why the game has regen central defenders at 5"6, why the transfers all to one club mess up the game, why all squads from games become unbalanced, why there are a zillion problems with the mode? This is called "timed obsolescence". The game is intentionally designed to degrade so you get off career mode and start wasting money on FUT.
Career mode will remain awful until a rival like PES severely overtakes FIFA. That game could bypass Fifa's monopoly on legal rights with an online community all contributing to an editable database. But if there are any startup player/manager games out there being developed, I'm sure EA has the purchasing power to buy them out before they get any good.
The best hope is probably that PES comes good. But why is that game also perpetually rubbish? Konami too want their gamers wasting money on online modes.
I guess the point of this thread is to help readers from getting sucked into false hope that one EA will make a good career mode. It's not in their interest to do so.