Sennin Buraku started in 1956 and is still going, though it has no official volume releases and isn't serialised in a dedicated manga magazine.
As for Sazae-san, it's actually consistently the number one anime in the ratings, too. Shows that a lot of western fans like and assume to be popular in Japan (like Bleach and Naruto) are rarely in the top 10. I checked out the rating since several months ago and Naruto was occasionally in the top 10, Bleach was never there, Sazae-san was always number 1.
Sazae-san has nothing on the British soap
Coronation Street which has 7197 episodes since October 30th, having started in 1960.