There is a now disproven maxim that says something along the lines of "10,000 hours of diligent practice are required to develop proficiency at a skill or activity". Of course, with sports, studies have been shown that the practice time accounts for only 18% of the success of those who become world class at their pursuit. Other factors include genetic predisposition (so called general athleticism), specific athletic prowess (just right for the particular sport), play and training in play situations, mental disposition, and luck.
Truly good riders have all of the necessary parts, including instincts, competitive personality and opportunism, fortitude, high pain thresholds, superb general and specific training, as well as natural athletic prowess. These folks are somewhat rare.
How this relates to the OP's premise, I have no idea. But, I'll agree that one can learn to enjoy bicycle riding with much less than 10,000 hours of in-the-saddle time. It's less gross motor technically frustrating than, say, tennis or the biathlon. But, all sports are hard. The limit is how gifted and committed you are, and the costs and risks you're willing to bear to succeed.