Yeah, the period of a uniform $30 buy-up is definitely over. Here's an evening in March 2019: $30, $20, $10, or no Saver, depending on the flight. I don't know if these are being set based on other carriers' schedules, or if it happens automatically, based on available underlying fare class.

For the curious:
$99: L ($30 difference)
$211: H (so no Saver would be expected here)
$114: G ($20 difference)
$124: K ($10 difference)