I'd presume if they can get the recovery rate and refurbishability rate high enough, they'd charge extra to companies that make them launch without recovery versus more flexible scheduling to guarantee recoveries.
In terms of weather, I reckon they could have a secondary site to land if weather prevented it in the primary zone. If you mean in the interim before approval of domestic landings on or near launch sites, spaceX probably has pre-existing contracts to do launches. Maybe they would discount them a bit for a better window, prior to Air Force/Regulatory approval.
Because recovery reduces the capability of the rocket. If you look at SpaceX's web site you'll see they plan to have two versions of the Falcon 9 and Falcon 9 Heavy. One version will be recoverable, and one will not. A customer that needs ever last m/sec out of the launcher will not be able to use the latter.