Precisely BECAUSE skill and strength are developed, but Talents innate.

That is more like how most people are strong with some flows but not others, and men generally stronger with Fire and Earth, women with Air and Water, while average strength in Spirit is roughly equal. A channeler can work with Fire weaves all day, every day and never get one whit stronger or more skilled with Water--but will necessarily become more deft and (initially) powerful in EACH weave that uses Fire. Everyone is inherently built to be stronger and more dexterous with some flows than others, like the brushes, overall strength builds with use until it peaks and Talents are all-or-nothing, but skill is always subject to improvement. The weakest channelers can never develop much skill even if they HAVE a Talent, because they cannot channel the Power with sufficient consistency and quality to exercise and thereby improve their skill.