I can't imagine my boys not earning their Eagles or my daughters not earning their Personal Progress. I would like my boys to earn their Duty to God, although I'm not as worried about that.
I don't think it's appropriate to hold something like a child's driver license over earning such an award.
I like the idea of teaching our children correct principles, modeling those principles in our own lives, and then giving them enough rope to either be productive or hang themselves. Not literally. Obviously at some point you step in and take drastic steps to avoid major life changing issues.
Children who are rebellious, lazy, doing poorly in school (I'm thinking really poorly, not just like B average poorly, but to the extent where they are being irresponsible), bad drivers, or otherwise not deserving of a driver license should not receive their driver license. That's probably not the real list but rather one I just made up right now and am not going to think much about. The point is that each child is different, so when it becomes time that it is an issue, you work it out with each child individually.
I can see daughter #2 coming straight out and telling us she doesn't even want to drive even if deep down she is desperate to. If there is something she is worked up about related to some award she doesn't want to be pressured to get, everything else in the entire world, good or bad, can be stacked up on every side, and she will retain her laser focus on not wanting to earn the stupid award. She will even be convinced herself that she doesn't want to drive. Until she wants to, at which point she will forget that she just told us 5 minutes ago that she doesn't care if she can drive.
Daughter #1 will have her Personal Progress earned the first day it is possible to have it whether or not there is any external reward for it.
The kids will be expected to help shuttle their siblings around as part of earning the privilege of driving. My parents didn't make me pay for my portion of the car insurance, but I think it's a good idea for them to understand at a deeper level that the cost of a vehicle is more than just the gas you put into it. Better grades and no tickets means lower insurance costs. You have to find a job and balance your time wisely in order to keep your grades up and earn the money you need and still participate in family and school activities.
I want my children to be responsible. If they are, they will probably earn their oh-so-important awards anyway just because they are responsible. If they are not responsible, not earning their awards may be a sign of that. They may also be very responsible but simply have to make decisions about what is important to them and the Eagle or Personal Progress may not be that. With the kids in my troop, I can tell within a few weeks of working with them whether or not they will get their Eagle. I think I know my kids a lot better than that so there should be no surprise to anyone if they earn it or not.