It depends on the offense, but there would never be 1000 different plays. Maybe 1000 different combinations, but certainly not 1000 plays.
Guys like Paul Johnson and his Flexbone and Mike Leach and his Air Raid MAYBE have 50-75 total plays in their offense. And on game day, they take 20-40 of them in with them. They watch film and narrow down to the best 20-40 plays against that week's opponent and they practice them nonstop during the week.
In the case of Mike Leach's air raid, they could literally create hundreds of different plays off of a single play call. For example:
Mike Leach's favorite play call is Six, known to the rest of you as Four Verticals. If he calls Blue Right Six (Blue Right being a split back with a tight end formation) he can add a tag to the end of that play to take advantage of something they see on film or from the coaches booth. Think of it like a hot route, but pre-determined. So it could become Blue Right Six Y Shallow. Which gives you the same play, everyone running verticals except the Y receiver (the tight end) changes and runs a shallow cross. Using one single play as a base, Leach is able to create dozens of plays.
It is the same concept for Chip Kelly. Oregon literally runs no more than 12 plays in a game. They are inside zone, outside zone, counter, speed option and then play action off of all of it. Where they get multiplicity is via formations, shifts, motions and tags. They can run their base 12 dozen plays out of dozens of formations. They can take their base inside zone and add an option call to it and make it a triple option. They can take their base outside zone and change the read from the defensive end to the three technique defensive tackle (midline option). They can take their base outside zone call, change the blocking call to have uncovered linemen pull and you get the buck sweep that Gus Malzahn runs all day at Auburn and now Ark State. When you're running at warp speed and signaling in plays fast, you can't have 150 different plays.
Nebraska in 1996 ran:
10 different outside runs
19 different inside runs
16 pass plays
That is it. That was the entire offense. Now each of these plays could be mirrored to go the opposite direction and could be run out of multiple formations but in the end, the Nebraska playbook in the 90's was 45 plays.
That is the trend in football, especially in high school but now in college and even somewhat in the pros. Less plays, more formations. It is so much easier to teach a new formation than it is 150 different plays. The most successful offensive teams at every level are those that perfect a dozen or so plays and run them over and over out of different looks.
That is where EA gets playbooks wrong. I made a thread on here a while back about Modular Custom Playbooks. Where I said instead of having certain plays be in certain formations, when doing custom books, you should be able to select the plays you want to run, then select the formations you want to use and then you'll have every play of your offense available in every formation.