The '87 Game 4 loss was a single missed three, by Bird, on the buzzer. All the Celts starters played the entire game w/o a break. In other words, no Sasha/no Luke off the bench for the C's. The '87 Lakers had Thompson, Green, and slew of others sub-ing in & out creating speed (and clogs in the middle) to break up the C's half-court set. It was a mismatch, favoring the Lakers, which the Celts had almost won.
In contrast, the '08 Lakers simply blew it big time. They're overrated from the start. All the Celts needed in '87 was a healthy Walton and Sichting and we would have won.