Treasuries are some of the most liquid instruments available, it is not a “liquidity” issue like “How do I line up buyers for all these weird, hard-to-price assets”.
And the measure put in place by the Fed is not a liquidity back stop, it is a value/solvency bailout, or kind of capital infusion. This is what SVB was trying to do on Wednesday, raise capital. That should tell you it is not a liquidity problem.