Most of my beers are at FG and fully conditioned at about a week. Some are at FG and fully conditioned in 4 days. I've gone fully grain to glass in 15 days (10 days fermenter, 5 days cask conditioned) but could go faster if I wanted (as quickly as a week grain to glass were I to force carb my house Mild).
Pros are faster because (as said), they pitch a proper amount of healthy, viable yeast, control their fermentation temperatures, and aerate properly usually with pure oxygen. What I found works well is to chill your wort to a couple degrees below your fermentation temperature, pitch cooler, allow it to warm during the lag to your fermentation temperature, hold it there during most of active fermentation, and then once it's wrapping up fermentation, raise it another couple degrees. Everything goes faster, and cleans up after itself faster. In other worse, start cool and go up, never start warm and go down.
What most homebrewers do is pitch warmer than they should, and either leave it warm or cool it down, and then after the heat spike of fermentation, the temp of the beer actually drops and it slows the conditioning phase.