Baseball is only loosely a sport, with comical amounts of dead time. I look forward to them adding a pitch clock at some point just to make them get on with itMisleading metric. I’d guess this means time after the ball is hiked or kicked. If that’s the measurement, baseball would only measure from the the ball or tennis after a serve.
But tennis involves lots of standing around, tv time outs, punching line judges, etc. yet there's a heck of a lot less dead time in tennis than there is football.
I think football should only have a five or ten second clock stoppage for incomplete passes, first downs or plays out of bounds. That would get game action back up and possibly take us back to twenty or even twenty five minutes of actual game play per game, doesn't seem unreasonable.