Fangraphs cost of a win in FA, 2020: $9.1 million/WAR

Trout salary/projected WAR in 2021: $5.4 million/WAR
Betts: $5.6 million
Stanton: $10 million
Arenado: $8.5
Cabrera: N/A, projected as negative WAR
Strasburg: $10.3 million
Votto: $225 million (lol)

Almost all are underpaid https://twitter.com/DannyVietti/status/1357410079713107970

A word on Stanton, Cabrera, and Votto (excluding 2020 because of short season):

Stanton $/WAR since extension (after 2014 season): $7.1 million
Cabrera (before 2014 season): $12.7 million
Votto (before 2012 season): $6.2 million

This is without even considering arb and pre-arb

anyway TLDR;

every big extension is either under or near market value, without even considering the unfathomable underpayment during pre-arb years that these superstars faced. not to mention, it actually matters to fans to keep superstars around