Tom Brady eventually wound up signing with the Tampa Bay Bucs and ed his new franchise to a Super Bowl victory in 2020, something Brady wanted to accomplish with his child hood team.
In an article from Bleacher Report, Brady had made it clear that the 49ers were his top destination in free agency but the 49ers already had a QB on the roster that had just led the team to a Super Bowl.
Kyle Shanahan and John Lynch opted to stick with Garoppolo over the legendary quarterback.
From B/R Article:
Brady had something to prove in 2020 and led his new team to a Super Bowl victory, something that he wanted to do with the 49ers.
Also, from everything I've ever heard about the relationship between Tom Brady and Jimmy Garoppolo, it never sounded like it was a true friendship. Tom Brady is a competitor and I believe he viewed Jimmy as a threat to his job security.
The quote above came from an article about Jimmy Garoppolo where he spoke about his time with Tom Brady.
It appears some of those politics are still alive and well today.
"Feels great, baby"