Because if you're there in front of the crowd, your total wait time for the day is going to be less. 45 at the beginning, yes (or really, 30 if you're at DHS by 8:15 and they open at 8:45). With being at the front of the crowd at RD, you're (theoretically) going to be in the front of the crowd for everything. Instead of short, almost non-existent waits at rides, you'll have no waits, and over the course of a day/morning, short waits add up to longer time waiting. For us, though we try, it's pretty typical we don't get to MK until the opening show starts, so we're at the back of the RD crowd. Consequently, our Peter Pan wait is around 5-10 minutes. Not big in the scheme of things, but in the meantime, Josh, who got there at 8:15 and was at the front of the crowd, has ridden Peter Pan, Pooh, and Barnstormer by the time we're off Peter Pan. So, we're two rides behind him at that point, and the waits only build from there. We can still complete Fantasyland in 90 minutes-2 hours and be outta there by the time the big crowds arrive, but he's already on his way to Adventureland after hitting Haunted Mansion and Frontierland. By the end of the morning, he may have waited 45 minutes total at the beginning of the day, with no in-park waits, whereas I have waited longer than that in total, but with 0 minutes at the beginning of the day and instead all of my waits coming in smaller increments inside the park. At the end of the day, Josh is going to have done more rides than me with a shorter total amount of waiting.