Don't expect that to last more than a year or two, assuming it's even still a problem for the best voice-generation AIs. Generating high-quality is the hard problem; generating specific high-quality samples is, by comparison, a lot easier.
Remember when Stable Diffusion was released a year ago and one of the big artist copes was "sure, it can generate random images, but it'll never be able to generate the same character repeatedly!" They were already wrong because Textual Inversion and DreamBooth were already published, and soon enough, ported to SD and now people could dump out thousands of images of the same character in the same consistent style etc (and did).