Everything about them is different.
Smith is more deliberate and conservative (although some will say he has been coached that way). Cousins is a bit more free-wheeling and is more of a gambler. Before this year.....many would say Smith won't win you many games....but he also won't lose you many either. That changed this year as Smith showed a bit more downfield attack.
I'm sure money has a lot to do with it....but Washington could never bring themselves to hitch their wagon to Cousins. Gruden must prefer a more "calculating" QB rather than a risk-taker.
I would think the Jets get in line for the Cousins sweepstakes.