Bet on every number but 0 on a roulette wheel
Not 0: you and your investors make 3 billion this year
0: you and your investors lose your 20 billion you have invested, and the government bails out your depositors who kept 200 billion with you
This stylized bet is a good deal for the investors and management and bad for the government. Sometimes investors lose everything but it's still a very good bet in expectation. This stylized example is a case of "privatized gains, socialized losses".
Then the question is: was SVB reckless? They could have been less reckless by covering their interest rate exposure, but the fed has an equity to deposits ratio requirement, and getting any equity to invest requires a return. IMO they should have either diversified their business or stopped opening new accounts for tech companies because when depositors are uninsured and concentrated in the same industry, that is risky.