They have to demonstrate value absolutely, but you're forgetting about the denominator of cost, and to a large degree so is the industry right now.
To take this argument to an absurd level, if Fable generating a feature cost $100,000 and Sonnet generating the same feature cost $1, it wouldn't be enough that Fable is marginally, significantly, or even dramatically better, because the cost difference is so outsized. For a variety of reasons, the true cost of tokens for frontier models is downplayed at multiple points (whether it's through AI companies running off funding, companies prioritizing AI adoption over AI costs, etc.)
If cost is not an issue at all, the best thing is always preferable regardless of cost. But in most cases, and AI is no exception, eventually cost will be an issue.
To take this argument to an absurd level, if Fable generating a feature cost $100,000 and Sonnet generating the same feature cost $1, it wouldn't be enough that Fable is marginally, significantly, or even dramatically better, because the cost difference is so outsized. For a variety of reasons, the true cost of tokens for frontier models is downplayed at multiple points (whether it's through AI companies running off funding, companies prioritizing AI adoption over AI costs, etc.)
If cost is not an issue at all, the best thing is always preferable regardless of cost. But in most cases, and AI is no exception, eventually cost will be an issue.