I cannot tell you the AMOUNT of times I've pushed down every outer turret in the top lane, then had a teammate call for everyone to "gRoUP mID." Never mind the fact that mid lane has all of its outer turrets up and that it's significantly easier to be flanked there.
Even if we DO ace the enemy team, odds are we'll only be able to get a single turret. Maybe 2/3 if we have Baron, BUT the point is that going top lane would've obviously benefited us more. A turret and inhib without Baron, and maybe a WIN with Baron if we had gone top lane. As a top laner, I feel like split pushing is often worthless if you can't get an inhib BECAUSE your team will NEVER group top and finish the job.
People have to realize that it's infinitely easier for a single person to get an outer turret than an inner turret. Top laners shouldn't devote themselves to trying to reach inhibs BUT to trying to break every outer. Grouping should then be used to break the inners.