He is indeed playing Bilbo. Peter Jackson wanted him so much he delayed filming to accommodate filming Sherlock season 2.
Whilst it is superb, you have to take into account that they produce three per year while a season of, say, Elementary is over 20 episodes. In the UK we can't compete with high volume output - many of our shows have seasons of five to ten episodes. Twelve maximum, apart from soaps.
I do believe your crap TV is probably way worse than our crap TV though...
PS - I wouldn't get your hopes up for too many more Sherlocks - both leads are becoming movie stars and probably haven't signed long term contracts for Sherlock.