I def see people in USPSA getting better much quicker these days than in the past. There is an intense focus on training & practice and a cadre of professionals dedicated to master self-improvement.
Good read on the topic...
Money quote: "What the second half of the 20th century did see was a steady increase in the amount of time that people in different areas devoted to training, combined with a growing sophistication of training techniques. This was true in a huge number of fields, particularly highly competitive fields such as musical performance and dance, individual and team sports, and chess and other competitive games. This increase in the amount and sophistication of practice resulted in a steady improvement in the abilities of the performers in these various fields—an improvement that was not always obvious from year to year but that is dramatic when viewed over the course of several decades."