I think Mookie will be an elite player for the next handful of years. Then he will slip into being merely a very good player for a handful. Then he will slip into being an above average, down to an average, player by the end.
The first stage, we will mourn that (assuming) he is gone, watching him put up tremendous numbers for another team. The second stage, we will note that while he's really good, maybe he isn't worth all that money. The last stage, we'll think, yeah, I wouldn't want to be paying him that kind of dough.
Though, of course, by the time that last stage comes, inflation will mean that he isn't getting paid the same, relatively speaking, as he would be in the first stage (unless they make the contract work that way).
It's always painful to see great players leave your favorite team. It's also painful to be locked into ridiculously huge contracts.
FWIW, here were the top 10 paid players in 2019 (from:
https://www.thestreet.com/lifestyle/highest-paid-mlb-players-14880433 ):
1. Strasburg - 38.3m - Won the WS
2. Scherzer - 37.4m - Won the WS
3. Grienke - 34.5m - Lost the WS
4. Trout - 34.1m - Missed playoffs
5. Kershaw - 31.0m - Made playoffs
6. Price - 31.0m - Missed playoffs
7. Cabrera - 30.0m - Missed playoffs
8. Cespedes - 29.0m - Missed playoffs
9. Pujols - 28.0m - Missed playoffs
10. Verander - 28.0m - Lost the WS
Just getting a sense of whether having a player on that kind of contract makes it more or less likely for you to win it all. Two won the WS, two lost the WS, 5 made the playoffs, 5 missed the playoffs.