Yes, the learning curve is less of a problem and, yes, a single, universally applicable convention that makes code more easily understood by coworkers would be worth a major effort. But There will still be new members to your programming group so the problem with your convention's learning curve cannot be ignored completely. You'll probably have to take the premise about more easily understood code on faith. This kind of thing is very difficult to study empirically. Moreover, a study that supports your exact standard is unlikely.
Small changes can have large effects.
If most programmers don't willingly adopt the convention, it will be sabotaged. It is very easy to follow a standard in a meaningless way and that is what people who are told to throw out all their previous ideas about naming conventions may do. When planning a convention, it is very easy to overlook situations in which that convention is inappropriate. Adopting an existing convention does not solve this problem because it is also very easy for those who write about, or test, the virtues of a convention to overlook situations in which it is inappropriate. A convention that isn't or can't be followed almost all the time may cost more than it is worth.