No--it was merely eclipsed over the past 2 decades by the larger Theater District that is north of the Tremont/Boylston intersection:
Boston Opera House: 2,677 seats.
Paramount Center: 910 seats
Modern Theater: 185 seats.
Orpheum: 2,700 seats.
AMC Boston Common: 4,500 seats.
So, let's see... 10,972 seats. How many seats does your "Stuart/Kneeland" Theater District offer?
Wang Center: 3,600
Emerson Majestic: 1,200
Wilbur: 1,200
Shubert: 1,600
Colonial: 1,700
Semel Theater: 261
Charles Playhouse: 700
10,261 seats - guessing I might be missing one, but, pretty much the same thing (well, except the majority of the seats here aren't a movie theater but actual stage theater). I mean, don't get me wrong, lower washington has become a second-theater/entertainment district, but, if someone says the Theater District, I always think Stuart St.