It's not nearly that simple, though. You are ignoring capital requirements. For things like Treasuries, you don't need any capital % against it. ($100 in deposit -> $100 in Treasuries, if you borrow at 1 and lend at 4 you made a 3% spread on $100). But for risky things that might yield much more, you might need to reserve far more, meaning you need to fund part of it with equity. ($100 in deposit but with a 50% capital requirement means you can -> buy $100 of high-yield stuff, but you need to use $50 of your equity to do so)
There's other epicycles to this too. For example, a bank can just "buy" deposits through a correspondent bank (a bank-for-banks). So the direct connection between your kind of borrowing and kind of lending, particularly when its consumer / credit card stuff, can be tenuous. In SVB's case, though, all of the stuff happened in a tight echo chamber ecosystem -- SVB got deposits from tech cos, who got money from VCs, who were working off of capital call LOCs from SVB. So your observation is germane.
There's other epicycles to this too. For example, a bank can just "buy" deposits through a correspondent bank (a bank-for-banks). So the direct connection between your kind of borrowing and kind of lending, particularly when its consumer / credit card stuff, can be tenuous. In SVB's case, though, all of the stuff happened in a tight echo chamber ecosystem -- SVB got deposits from tech cos, who got money from VCs, who were working off of capital call LOCs from SVB. So your observation is germane.