Thanks for the analytics
Steelers biggest problem is someone else is willing to pay more than they are and Bell wants that number - given how he threw his teammates under the bus yesterday regarding how he was ready to play Jax but other teammates were not I do not sense any loyalty to the Black & Gold (which is fine, just saying this is not like some players factoring where they play into their calculations). Bell just wants to get paid.
The team willing to overpay might not be using reasonable market value but it is market value (see, e.g., what Danny Snyder is paying Alex Smith).