Now... The long term prognosis.....
One thing thing that makes learning new material elusive it that your brain only does part of the heavy lifting. Muscle Memory is another BIG part of playing any song. Muscle Memory only learns by doing... again and again and again and....
I have had some pretty impressive experiences with muscle memory. But the one thing I do know is that I have to keep practicing, as long as I want to preform any given song. My experience is that practice is the care and feeding part of learning to befriend my Muscle Memeory. Plain and simple it is the key to all performance. To be ready for preformance, any song will require that I practice it again and again. No mater how well I drill a song, once you stop practicing, the fine details start to slip out of control. You have to feed the Muscle Memory regularly or it gets foggy and you loose the fine details that make a performance memorable.
On the other hand once I commit a song to muscle memory, it can usually be brought back preformance standard with very little practice. Even if I don't play a song to years and I don't have a cheat sheet to work with, my muscle memory still remembers more than my intellectual mind does.
I have had original songs that I didn't play for years. However once I started playing them again my fingers remembered what the chords were and would frequently just grab that chord all on their own (even bazarr jazz chords) seemingly out of thin air! If I couldn't remember a given chord, all I had to do is keep playing the parts I could remember, and my fingers did all the walking that was needed. Then, almost magically, my fingers would just grab the missing chord out of thin air. This is a truly amazing experience, that shows how powerful Muscle Memory is to musicianship.
This is your friend... Muscle Memory. It is frequently overlooked, but it is never missing in a great preformance. Unfortunatly Muscle Memory requires that you continue to practice, but the songs you choose to continue playing will become much easier over time. Muscle memory is able to do a great deal of what it takes to pull off a great preformance. However, there are no short cuts too the care and feeding of a growing Muscle Memory. Like most things musical, if you want to be great, you will have to get used to spending regular time in the wood shed.
Captcha is a total pain in the........