And they did it in the tougher Western Conference (FAR tougher than the East for the early part of that 5-year run)...
But I'm glad they'll (likely) only win 3 of the 5. Any team with too much success usually turns me off pretty quickly. If the NBA became a one team league, what's the point of watching, unless you're from SF?
As for consecutive Conference titles, before the Raptors, CLE just won 4 straight, giving us four consecutive GS-CLE Finals, which got tedious...
before that was MIA winning four straight (meaning BronBron was in 8 straight, winning 3)
The Lakers recently hit 3 in a row, multiple times... 1987-1989, 2002-2004 and 2008-2010...
So did the Bulls... 1991-1993, and 1996-1998, winning all 6 titles
The Pistons also had a three-peat of Appearances, 1988-1990...
Then the Celtics did a four-peat, 1984-1987, while the Lakers did 7 of 8, 1982-1989
But you are correct, the last time anyone (other than LeBron) saw 5 Finals in a row was the Celtics, who did 10 in a row, and 12 of 13, from 1957-1969, winning all 12 titles (PHI won in 1967)... this while the Lakers appeared in 9 of 12, from 1962-1973, winning only one of the nine, in 1972.
From 1957 until 1989, for 33 years, the Finals had either Boston or the Lakers, or both, just about every single year. Only 6 times, out of 33, were they both shut out. The Celtics went 16-3 in their 19 appearances, and the Lakers went 6-12 in their 19 appearances... but 8 of those losses were to Boston... and 2 of the 3 Boston losses were to LA (1985, 1987)