As a fellow golfer of many years(12 serious years), you will get as good as you allow yourself to be. You don't have to practice a lot, but you have to practice the right things; grip, stance, ball position and tempo. Over and over. Repeatably. Keeping it simple and not practicing too much at ingraining the sloppy techniques we develop is the key to breaking a plateau. I broke mine when I simplified my routines drastically and committed to one philosophy. I lowered my handicap from 26 to 12 in one year.

As a metaphor for life, golf is apt because they both become easier when you take the counterintuitive approach, they both simplify with relaxation and the both ultimately turn on confidence and attitude. You have reached a plateau, but not your limits. I wish you much luck and many joyful days on the course......and in life in general.