If you're punting on 2020, 2021 AND 2022, you may have just as well re-signed Mookie and traded away all the shorter term contracts (JD, Price, et al). You would have gone under the lux tax in 2022 at the very least and managed to retain one of the most marketable stars Boston has ever had. It just shows me that it was about cost savings long term rather than just getting under the lux tax for that one year.
"Hey, we're not going to compete until 2023 so we gotta get under the lux tax in 2020 by dealing Mookie."
"Couldn't you just re-sign him and get under in 2022? If you're not planning on competing until 2023, it at least gives the fans something to watch."
"Pay no attention to the man behind the curtain!"