GURPSよろず

　The Basic Set uses words like “natural,” “inborn,” and “gift” to describe Talents, implying that Talents are innate.
Scientific research bears this out at least somewhat; the brains of certain people do appear to be wired for music, math, etc.
Racial Talents (p. B452) might be similar – it isn’t difficult to imagine that, say, certain apex predators have a knack for stalking – and may even reflect physiological adaptations to groups of related tasks.
The point is that as written, Talents aren’t acquired.

　To preserve the dramatic niche of PCs who start out with Talents, it’s fairest to rule that the untalented can’t “learn” Talents through means less radical than ultra-tech brain implants or powerful supernatural intervention – or unless Talents as Training (p. 25) applies.
If anybody could come along and buy Natural Copper and Business Acumen in play, then players who allocated starting points to these things instead of buying truly inborn traits like High Pain Threshold and Voice would be penalized for their sacrifice.
Perhaps worse, the cachet of strong character concepts like “natural detective” or “born businessman” would evaporate.
Much as Magery and Power Investiture define who gets to be a spell-slinging wizard or a miracle-working cleric, mundane Talents should more-or-less permanently separate heroes who are cut out for a vocation from those who aren’t.

　By definition, though, those who are talented have a gift for learning the things their Talent covers.
Thus, it’s fair to permit PCs who get a foot in the door by purchasing at least one level of Talent to use earned points to improve that Talent later on, subject to the usual limits. Perhaps they’re realizing their full gifts! (Maybe heroes without Talent should be able to realize their gifts later on, too, but they didn’t pay for the privilege.) And this fits with the way the game works: Most characters have to study each skill in a related set separately, or raise the underlying attribute; “naturals” can improve all of those skills more cheaply. Think of the option to improve existing Talent as an extension of the learning-time reduction for the Talent’s skills.

　To witness this in action, see GURPS Dungeon Fantasy.
That series often assumes that everyone who follows a particular profession or belongs to a certain race starts with a low level of some key Talent, which they may improve later.
Outsiders simply don’t have the option.