This is far more serious than simply owners wanting him out.
Anytime the US Attorney's office starts looking into a business and its operations it's not a good omen for management.
The Feds don't act on investigations/prosecutions unless there is something they feel is potentially actionable and you don't see the frivolous suits we sometimes see brought by state and local authorities who may be in part trying to make a partisan political statement.
The other factor is Federal sentencing guidelines are harsher and parole is not a factor in many cases brought.
The Feds are able to leverage this against defendants so that they can force a plea before 80% of these cases go to trial.
If Snyder is found guilty of criminal fraud, tax evasion, etc. he may be facing jail time.
This calculus goes way beyond merely selling the team and going to live on his yacht because the owners scared him with a potential vote to remove him.
Jerry Richardson and Donald Sterling never faced these kinds of allegations before being forced out.