1-Numbers: Forcing a team to sustain long drives results in reduced success ratios and playing a fundamentally sound defense yields better results than consistently gambling with a high risk, high reward scheme. Drives starting at the 20 results in scores 20-25% of the time, while drives starting at the 40 result in scores 40-45% of the time, while drives starting at the opponents 40 yield scores around 65% of the time. So by taking measured risks and insuring your players have a thorough understanding of your scheme, are confident in their reads and can play fast, makes the opponent execute at a higher level to beat you. So by limiting big plays you give your defense more opportunities to create stops/turnovers by making the offense sustain drives.

2-Talent: Usually (and I say usually, so there are exceptions) two types of teams will play an extremely high risk/high reward style. Teams that are either grossly overmatched from a talent standpoint and can't play within the framework of the scheme above and consistently win the 1 on 1 battles. They have to throw caution to the wind and hope they create more big plays than they allow. Rocky Longs New Mexico teams are a good example of this type team. They basically have nothing to lose, so they go down swinging and occasionally pull a surprise. Teams that are vastly superior athletically and can afford to take risks because they can play man coverage and make up for mistakes with pure athleticism. Even in that scenario teams that can do this, do not do it for 60 minutes. The most recognizable example of this would be Buddy Ryan's defense on the '85 Bears, or Gary Patterson's TCU defenses when they were in the MWC. Usually when we would play teams that blitzed a lot it was because they had inferior talent and were just looking for a way to disrupt out offense. The teams that gave us the most problems (Centennial if you are familiar with Arizona HS Football) played mostly base and made sure their athletes had all gaps accounted for.

That is it in a nutshell and it just comes down to philosophy and of course talent. The other thing you have to keep in mind is practice time. Do you want to spend your time teaching players multiple complicated and/or risky blitzes that expose you if one player goes to the wrong gap, or doesn't cover another players assignment? Or, do you want your team to be fundamentally sound, be prepared and confident in their keys and be able to master a few key situational pressure packages? For most coaches, it is probably the latter.